This is scaring so many people, but is full of mistakes and has no scientific credibility. It's written by a couple of businessmen, with a foreword by a retired admiral, and no scientific peer review. For instance they misunderstood a paper about "lethal heat" which was referring to the heat waves we have at present, 30% of the world population experience this every year already, e.g. Europe this summer. It is only lethal in the sense that 1 in 10,000 can die if they don't take the precautions you should take during heat waves such as drinking plenty of water, finding shade in the middle of the day, and taking especial care of the elderly and babies. It's the sort of weather where beaches are crowded with people enjoying the warmth and sunshine, and they are fine so long as they take simple precautions and make sure they have some shade in the middle of the day. This was a rookie error and they made many other mistakes like that.

This story should never have been run on mainstream news. I was glad to see that at least some of the most highly regarded news sites didn't run this, such as the NY Times, Washington Post, The Times, The Guardian, BBC News, Nature, or the Smithsonian magazine. I was very disappointed to see CNN, the Independent and several others running it without explaining its dubious credentials,

As an example, Spratt and Dunlop, the two Australian businessmen, say that in their worst case scenario, by 2050,

"Thirty-five percent of the global land area, and 55 percent of the global population, are subject to more than 20 days a year of lethal heat conditions, beyond the threshold of human survivability,"

The Nature paper they cite, Global risk of deadly heat , was calibrated to 30% of us facing 'deadly' heat waves in 2000. A careless reader might think that meant  "beyond the threshold of human survivability" but that clearly didn't happen in 2000.

The paper explains with examples such as the 2003 heat wave in Europe which lead to a vulnerable 1 in 10,000, especially infants and old people, dying. All those deaths are preventable by taking adequate care of vulnerable people in hot weather. Indeed, after the extra deaths during the 2003 heatwave the UK, for instance, added new alert levels and our news now issues many warnings to vulnerable people during every heat wave.

It is only at the higher warming level of 4°C that some small areas in China / India / Persian Gulf / Southern US for the first time reach the point where during occasional extreme heat waves it is impossible for a fit farmer to work in the fields for as much as six hours without dying. Very different.

Michael Mann, respected climate scientist at Pennsylvannia State University, calls their report "overblown rhetoric, exaggeration, and unsupportable doomist framing":

"Is it true climate change will cause the end of civilisation by 2050?" [spoiler alert: NO] by @AdamVaughan_uk for @NewScientist: https://t.co/xJrArcWgxm

— Michael E. Mann (@MichaelEMann) June 6, 2019

There are many serious errors. E.g. the billion figures displaced actually comes from a 2010 report by a German non-profit which gives this as an estimate of the population who live less than 20 meters above the mean sea level, a rather different situation.. Modern figures are around 100 million or so affected by sea level rise with "Business as usual" at the extreme level of a couple of meters or so sea level rise, and most of those can be mitigated by sea walls especially in developed countries; only a few million have to migrate, usually internally to the country affected. That includes Florida because of the porous limestone bedrock and Bangladesh because of the extensive low lying regions and difficulty and cost of sea walls. As for total migrants due to all causes, the World Bank says 140 million by 2050, again most of these internally to the affected countries.

He links there to a New Scientist article where he is reported as saying:

“I respect the authors and appreciate that their intentions are good, but as I have written before, overblown rhetoric, exaggeration, and unsupportable doomist framing can be counteractive to climate action.”

Climate Feedback has some other comments about it from various scientists including:

The “report” is not a peer-reviewed scientific paper. It’s from some sort of “think tank” who can basically write what they like. The report itself misunderstands / misrepresents science, and does not provide traceable links to the science it is based on so it cannot easily be checked (although someone familiar with the literature can work it out, and hence see where the report’s conclusions are ramped-up from the original research).

Richard Betts, Professor, Met Office Hadley Centre & University of Exeter
When they read this sort of thing, vulnerable people are paralysed with panic. It does no-one any service to stand by while this nonsense is presented as "climate science". If they had used reliable sources and summarized them properly it would be useful climate change debate. They used reliable sources that they hugely misunderstood, presenting those mistakes as the "truth" to other people who are not scientifically educated enough to check the sources. They also used unreliable sources like David Wallace Wells and propagated his mistakes. This is not useful in the Climate change discussion. It rather confuses people and makes vulnerable people scared and paralysed with fear, and often to the extent that they need drugs and long term therapy to cope with the resulting severe anxiety disorders (I spend hours a day most days doing my best to help such people).

Yet we have already done so much and there is so much more we are going to do in the future. California has already committed itself to produce 60% renewables by 2030 and all electricity from carbon-free sources by 2045, Joe Biden, currently front runner for Democrat nomination for 2020 committed to zero emissions for the US by 2050 if he is elected. If not this time, there are two more presidential elections before 2030 to elect a president committed to zero emissions by 2050, for the easiest path to 1.5 C.

Although worldwide most pledges are not yet sufficient for 2°C never mind 1.5° C, we have already knocked over a degree off the projection for 2100 in three years, target 3°C with current policies and unconditional pledges, and many countries are in the process of stepping up on their original pledges and over achieving, including India (already 2°Ccompatible), and China. The EU as a whole has a decent chance of joining the list of those who target zero emissions by 2050 (i.e. 1.5° C compatible) as a result of the "Green Wave" in the EU elections making them a significant element in the EU parliament. The UK parliament declared a "Climate emergency" and Scotland is in process of committing to zero emissions by 2045. Hopefully this is just the start of what will become an unstoppable momentum for change. We can do this, we can stay within 1.5°C and avoid all those outcomes in the IPCC worst case scenario. But whatever happens we do not risk loss of civilization or human extinction.

This is another article I'm writing to support people we help in the Facebook Doomsday Debunked group, that find us because they get scared, sometimes to the point of feeling suicidal, by such stories.

Do share this with your friends if you find it useful, as they may be panicking too.

USE THE IPCC WORST CASE SCENARIO INSTEAD

They argue that we should use their report in place of the IPCC one on the basis of a Nature paper saying that the climate researchers err in the direction of "Least drama". This is often used by climate catastrophists as a reason to listen to them.

The paper they cite was a position paper generating much discussion, with most agreeing that scientists go wherever the science takes them. The limitations that lead to underestimates (or overestimates) are limitations of science, not due to a bias against reporting or modeling the more extreme possibilities. Many processes are hard to model without well sub-kilometer scale meshes. These are approximated using parameterization, which can introduce errors and easily miss important processes. We aren't quite there yet, a global model is no use if it is so detailed, it runs slower than the real world climate changes, though local weather forecast models are already sub kilometer.

To take the example of sea level rise, the IPCC 2018 report presents the full range of values given in the literature. The NOAA could also do that, as they say, but that is due to huge progress in the field of predicting effects of glacier and ice sheet movement. And yes, back in 2013, there just wasn't the research avaialble to summarize. The IPCC didn't ignore this issue however, instead they told policy makers to allow for higher levels than they presented to take account of ice melt processes that weren't yet being modeled adequately in the literature..

Don’t read this report for an idea of the worst possible future in store for us. Instead, I recommend the IPCC’s example worst case climate change scenario. The IPCC say that we can still feed everyone through to 2100 even if the Paris agreement falls apart, but we likely lose nearly all the corals (to sponge reefs), much of the Amazon rainforest becomes savanna, we face increased desertification and deforestation, many people have to migrate more than 1000 kms as climate refugees, there's increasing poverty, reduced food security and reduced biodiversity. There is plenty of reason to work hard to prevent this outcome, to head rapidly to zero emissions, build in climate resilience, and prepare, adapt and mitigate the effects. However, we do not risk human extinction or the loss of civilization even in the worst case

SUGGESTS WE NEED MILITARY STYLED EMERGENCY MOBILIZATION TO TACKLE CLIMATE CHANGE (CONSCRIPTION?)

You can understand that a military officer might like this report, because they say the military should be used to solve our climate change crisis. Spratt and Dunlop say:

“Urgently examine the role that the national security sector can play in providing leadership and capacity for near-term,society-wide, emergency mobilisation of labour and resources, of a scale unprecedented in peacetime, to build a zero-emissions industrial system and drawdown carbon to protect human civilisation.”

Their basic argument is that the military are more efficient in emergency situations. It’s not entirely clear what “emergency mobilisation of labour and resources, of a scale unprecedented in peacetime” means, but it sounds like conscription. What else could it be? If you have some other understanding of this, do say in the comments.

Yes in a way, the military are often used for emergencies e.g. after hurricanes as they are able to mobilise quickly. But what are they supposed to do to solve something that needs such long range action and planning as a climate crisis?

HARE-BRAINED SCHEME

Is the Australian military somehow supposed to convert all the Indian and Chinese power stations to renewable power in an emergency operation? And fit solar panels on the roofs of every house in India?

Or is it the Indian and Chinese military who are supposed to do this, i.e. a worldwide coordinated military action by each country to retool its entire nation with renewables instead of fossil fuels?

They do not explain. We have a phrase in the UK "Mad as a march hare" which I don’t often use but I think this is a perfect occasion :). Also the term “harebrained” springs to mind.

(click to watch on Youtube)

Another video of mad march hares here.

Why not just help fund the Green Climate Fund set up for the Paris agreement to help India to change to renewables?

EXAMPLE OF GREEN CLIMATE FUND TO ENCOURAGE ROOFTOP SOLAR IN INDIA

India has a target of 40 GW of rooftop solar power by 2022, which needs about $34 billion investment. However it is hard to get this underway because it needs long term financing (rooftop solar power pays off over many years rather than instantly) which is in short supply in the Indian population - and they also are wary of the perceived risk.

The Green Climate Fund invested $100 million to an initial $250 million program to construct 250 MW of solar rooftop capacity across India. That will provide electricity for 290,000 households and expected to reduce emissions by 5.2 million tons of CO2 in the next 20 years. The idea is to demonstrate that the technology works and help pave the way to future private sector financing as the private companies see that there is money to be made here.

This is an earlier photo from 2011 connected with India’s “National solar mission”:

Rooftop Solar Panels Vrinda Manglik (Hyderabad)

How would the Indian military help here? Or the Australian military? It would surely cost far more to use soldiers to install these panels. Meanwhile the hope is that private industry will take off. Bear in mind that solar panels are expected to continue to fall in price rapidly over the next few years.

Many of the poorer countries are in a similar situation to India. They are keen to support renewables; they can see many benefits from them, but it is not easy to encourage their people, with their limited resources, to invest so much in renewables. That is why we have the Green Climate Fund, which could do with a lot more funding.

NUMEROUS MISTAKES IN THIS REPORT

This report has numerous mistakes packed into its ten pages. It would take ages to debunk everything. This would run to dozens of pages if I did. I will just take a few. I've already mentioned the heatwave mistake. I'll briefly summarize a few of the other main points in this article, then go into them in detail.

We are a species of "Least concern" according to the IUCN, widely distributed omnivores, live in many habitats naturally, can make artificial habitats for ourselves,, with our numbers increasing. We are descended from asteroid impact survivors. Our technology is so good, we have outposts in space and Antarctica. We are likely to evolve into something else, not go extinct.

The "Hothouse Earth" paper was widely misunderstood. It didn't contradict the IPCC. It was a hypothesis paper rather than primary research, focusing on feedbacks from tipping points such as the melting Greenland Ice and Anatractic ice tens of thousands of years in the future. Current emissions, they hypothesize, are "Stabilized Earth". We currently avoid both future ice ages and hothouse Earth. They hypothesize that with good stewardship in this century we can stabilize our climate for tens or hundreds of thousands of years. The. IPCC looks at centuries in future.

The article about the IPCC under estimating warming was a Nature Comment. Again not meant to be taken as "True" because it is in Nature. These often only put one side of a debate, and stimulate discussion. For instance, the uptick in CO2 emissions was no great surprise, half of it due to China as it both industrializes rapidly and also rapidly converts to renewables. It is expected to fulfill its pledge to peak emissions before 2030 and probably well before, Indeed, it, is expected to increase its pledge of 20% renewables by 2030 to 35%. Future temperatures for all climate scenarios are almost indistinguishable through to 2030 but diverge widely after that, depending on what we do in the next decade.

MAJOR MISUNDERSTANDING IN “55% OF OUR POPULATION ARE AT RISK OF DEADLY HEATWAVES BY 2050”

This is one of the things that many of the news stories are highlighting as one of its key “findings”. This is actually a misunderstanding of a paper in Nature.

Spratt and Dunlop say this, which seems very dramatic:

"Thirty-five percent of the global land area, and 55 percent of the global population, are subject to more than 20 days a year of lethal heat conditions, beyond the threshold of human survivability,"

It sounds awful. But what you need to bear in mind is that the paper they are citing also says that around 30% of us were exposed to the same “deadly” heat in the year 2000.

They cite this Nature article, Global Risk of Deadly Heat, which says:

“By 2100, 34.1% and 47.1% of the global land area will be exposed to temperature and humidity conditions that exceed the deadly threshold for more than 20 days per year under RCP 4.5 and RCP 8.5, respectively; this will expose 53.7% and 73.9% of the world’s human population to deadly climates by the end of the century”

(removed the error ranges for readability)

(They rounded to the nearest multiple of 5%, they are both approximate figures anyway, only accurate to a few percent and the paper also says they probably over estimated by a few percent or so in their model).

They explain what they mean by “deadly”, near the start of the paper. Every time there is a severe heat wave, there is an increase in the death rate amongst the elderly and vulnerable. Deaths of around one person in ten thousand.

One of their examples is this heat wave in Europe in 2003:

(click to watch on Youtube)

20% of the deaths in London during the heat wave and 70% of the deaths in Paris at the time were due to this heatwave

In the whole of Europe a total of 70,000 deaths are attributed to this heatwave. Yet that’s a small number out of the half billion population of the EU. About five million or so die each year. Causes and occurrence of deaths in the EU

Also deaths in heat waves are not inevitable, and countries don’t sit still when this happens. The 2003 heat wave lead to new heat wave alert levels being established in the UK:

  • Level 1 - Awareness - general vigilance during summer
  • Level 2 - Alert - triggered when heatwave temperatures are predicted in at least one region
  • Level 3 - Heatwave - triggered when threshold temperatures have been reached in at least one region
  • Level 4 - Emergency - where the heatwave is classed as severe and prolonged

Heatwave survival advice launched

It is a matter of adapting to cope, and public education. Vulnerable people can use air conditioning, drink lots of water, staying indoors at the hottest times of the day, and so on. Indeed, whenever there is a heatwave forecast, we have these guides in our press about how to cope with it.

During the 2003 heat wave, excess deaths in nursing homes in the UK rose by 43%. The hospitals and care homes need to make sure they have measures in place to cope with excessive heat

So, in short, the passage I quoted from that paper, which they misunderstood, warns that if we reach 3°C by 2100, the number of people who experience heat waves strong enough to increase the death rate of vulnerable people increase from around 30% to around 50%. Only a few people die in these heat waves, around 1 in 10,000. These deaths are preventable.

I go into this paper in more detail here:

CLIMATE ANALOUGES FOR 2080 FOR US CITIES

This is a project for US cities only, sadly. But it finds climate analogues in a warming world. For instance if you live in Washington DC, their map can help you find a city with climate similar to what you will experience in 2080. To work out the analogue they used the minimum and maximum temperatures and the total amount of precipitation (rain, snow etc) for the four seasons of the year. So a close analogue means the temperature range and the amount of precipitation is the same for all four seasons. A weaker analogue means that they are only roughly the same.

The online interactive version of it just shows the closest analogue, for high emissions is 4.9°C by 2100, and doesn’t tell you how close or far it is as an analogue, but it gives a rough idea:

For reduced emissions, 2.4°C by 2100:

We are currently between the two headed for about 3°C by 2100.

To explore how the climate changes for other cities in the US go here:

This is more significant for agriculture than for people directly. The US has had at least some climate related damage, and harvests lost. Let’s take the example of frost damaged trees losing their fruit. The problem is that the trees blossom earlier, sadly often before the last frosts of the year. They lose their blossoms which are much more sensitive to frost than twigs, and so do not fruit:

They need to breed new varieties, that blossom at the right time of year, but can’t just import varieties from a lower latitude (the day length hasn’t changed, just the temperature).

Meanwhile some are using mitigation methods to grow the same fruit as before, but protecting them from the frost. That’s mentioned in this podcast:

There are many groups involved in working on climate resilience, For the US: Climate Resilience Portal | Center for Climate and Energy Solutions

The US risks return of dust bowl conditions, and has to prevent and mitigate this.

All this is nothing you can't adapt to in a wealthy country and poor countries can too, more easily with some assistance from wealthier countries. But our climate is already permanently changed to some extent.

Not damaged particularly. Not worse. There have been larger changes more rapidly during ice ages when the climate is far less stable than in an interglacial.

Just changed. To get temperatures a few degrees warmer, and drier conditions and needing to grow new crops sometimes, all that takes some adjusting to.

It’s the change rather than the final climate that's the problem. The new generations of fruit tree will be fine, so long as they can blossom at the right time of year. Birds may need to nest at different times to synchronize with caterpillars. Your agriculture may need to adapt, you may need to be more careful about wildfires like someone living in a hotter country, you may need buildings that are more resistant to hurricanes and so on.

WHAT IS THE REAL HIGH TEMPERATURE WORST CASE?

The worst case with “business as usual” which we are not headed for is mass migration of humans from the hotter parts of the world such as the Persian gulf and the hottest regions of India, not mass extinction. Parts of Northern India of course are very cold near the foothills of the Himalayas and they will not get too hot for humans even on the very worst scenarios. We aren’t headed for a future where Nepal, Bhutan or Tibet will be too hot for humans on any scenario. Or Ladakh or Gangtok in India.

This is a map from a paper that studied the northern Chinese plain, where many farmers grow rice and work out of doors. It’s especially vulnerable because of the humidity. Even then the climate is fine for the rice. The problem is the effect on humans working in the fields.

The graph is here Nature Communications

The red means business as usual RCP 8.5, the blue is RCP 4.5 approximately what we are on so far with the Paris pledges and unconditional commitments, and the black is historical. The graphs are histograms showing the predicted number of days with at least 6 hours of maximum wet bulb temperatures for each bin in the thirty years time period from 2070 to 2100 in each scenario.

Over 35 °C then even the fittest farmers would not survive six hours of working in the fields. Work would have to stop.

They focused particularly on China but looked at two other study regions, India and the Persian gulf.

The dark red areas have wet bulb temperatures over 31 °C for 5% of the time, and risk 35 °C heat waves. You can see how it affects eastern China (above Taiwan in the map) also the coasts of the Persian gulf (but not the desert interior because it is so dry there) and Bangladesh, Kolkata and parts of Pakistan.

The figure is here Nature Communications

(with link back to the article page).

For other parts of the world we can go to another study here

This time it shows the yearly probability of a heat wave that has temperatures over 55 °C. Whether that has a high wet bulb temperature would depend on the humidity, and you can get conditions too hot in very damp conditions below that temperature, while you can survive temperatures well above this in dry conditions. So it’s not as precise but you can see that other areas that need attention would include southern US and northern Australia, and central regions of southern America. Orange means temperatures over 55 °C are experienced roughly every other year. The Persian Gulf area is another area singled out as being particularly vulnerable in other reports due to the high humidity combined with heat.

Paper here

So it does become an issue for some people already at 4°C.

The Persian gulf region is particularly vulnerable because of shallow seas, and intense sun, leading to hot damp conditions - the most difficult conditions for humans to survive in. Elahir and Pal, reporting in Nature, found that at "Business as Usual", many major cites could reach a tipping point later this century, where for the first time, conditions exceed the limits for human survival, with wet bulb temperatures exceeding 35 °C every few decades.

This is for a higher temperature rise usually estimated at about 4.9°C global warming from pre-industrial.

(click to watch on Youtube)

See.MIT press release:

Christoph Schaer wrote in commentary on this study (which he was not involved in) that while deadly heat waves have occurred recently in Chicago, Russia, and Europe, in these cases infants and the elderly were most affected. This he says

“Concerns another category of heat waves — one that may be fatal to everybody affected, even to young and fit individuals under shaded and well-ventilated outdoor conditions.”

So, such conditions as they describe can occur, but not at 3°C anywhere.

They can occur, towards the end of the century, but only at "Business as usual". We are not headed there. The IPCC worst case is 3°C by 2100, because it is not plausible that we continue to burn fossil fuels through all the transitions to a 4.9°C warmer world without doing anything to mitigate it. Even if improbably the Paris agreement fell apart (it is well established now since the rule book was agreed in December 2018), there is no way that we continue to ignore the crisis through to the second half of this century. Even in that worst case they predicted action, but disorganized and late, enough to keep us within 3°C.

As it is, we are headed for 3°C already with existing pledges and with a great deal of leeway to let us ramp up to higher pledges which we can definitely do in the next decade consistent with prosperity and increasing quality of life worldwide.

See my

CLIMATE MIGRANTS

Although they don’t mention it in the Nature paper, these people are not necessarily going to stay put as the temperature increases. At 2°C of warming already, many would need to move a distance of more than a thousand kilometers over a timescale of less than a century. The IPCC in 2018 referred to this Nature paper about migration:

“Here we show that in order to preserve their annual mean temperatures, tropical populations would have to travel distances greater than 1000 km over less than a century if global mean temperature rises by 2 °C over the same period. The disproportionately rapid evacuation of the tropics under such a scenario would cause migrants to concentrate in tropical margins and the subtropics, where population densities would increase 300% or more.”Potentially Extreme Population Displacement and Concentration in the Tropics Under Non-Extreme Warming

This of course reduces their vulnerability to heat waves.

Spratt and Dunlop, the two Australian businessmen, also claim that a billion people will be displaced by 2050. Commenting on it, New Scientist write:

The figure is a lot higher than most estimates. The World Bank says 140 million by 2050, for example. Breakthrough cites as evidence a 2018 report by Swedish non-profit, which in turn sourced it from a 2010 report by a German non-profit. That said a billion people live in areas that could be inundated by sea level rises this century – quite different to saying there will be a billion climate migrants by 2050.

The billion people figure in the quote from that report actually was for people within 20 meters of global sea level, which nowadays is considered way above even the extreme level for 2100:

Scientists have tried in various studies over recent years to assess the extent of the threat posed by sea-level rise. To appreciate the coastal area at greatest risk of flooding, it is necessary to first analyse current heights above sea level. This is not easy because no reliable topographical maps yet exist for many coastal areas.

At a rough estimate more than 200 million people worldwide live along coastlines less than 5 metres above sea level. By the end of the 21st century this figure is estimated to increase to 400 to 500 million.

In extreme cases relocation may be the only solution. A total of a billion people worldwide now live within 20 metres of mean sea level on land measuring about 8 million square kilometres. This is roughly equivalent to the area of Brazil. These figures alone illustrate how disastrous the loss of the coastal areas would be. ...

World Ocean Review, 2010

As New Scientist say, that is a totally different situation. It is about sea level rise, which can be mitigated by using sea walls, so they aren't necessarily going to move.

Also, that 20 meters is way above the likely rise by 2100 or 2050. It is above mean sea level, so not taking account of tidal range, but that hardly makes any difference The Bay of Funday in Canada has a tidal range of 16 meters, so about 8 meters above mean sea level. In the open ocean tidal ranges vary from zero to around a meter or so Global tidal ranges (NASA / JPL).

The NOAA extreme level for 2100 is 2.5 meters, nowhere near the 12 meters needed to reach to 20 meters above sea level even in the Bay of Funday.

Only a few of those billion people would be affected at that level. At sea level rise of 2 meters an estimated 187 million are affected by this 2011 report, but that's at "business as usual" and assuming no mitigation (such as sea walls).

The wealthier countries can mitigate sea level rises with sea walls, especially around cities, so only a few of those 187 million are affected by this. The poorer countries are more likely to solve it by internal migration. An estimate for Bangladesh finds that 0.9 million people of its population could be displaced by direct inundation by 2050 and 2.1 million by 2100, almost all of this in the southern half of the country.

Florida is especially hard hit by sea level rise because it is built on foundations of limestone, a porous rock. There is nothing they can do to keep out the highest "King tides" and storm surges, except build up. In a warmer world if we get as far as a 1.8 meter sea level rise, then according to one study, there would likely be 2.5 million Florida residents migrate away under a 1.8 meter sea level rise, most from Miami. 250,000 would likely leave San Francisco and nearby areas. Meanwhile Texas could see an additional 1.5 million immigrants, just because of the sea level rise.

'We're moving to higher ground': America's era of climate mass migration is here

According to Climate Central who specialize in detailed sea level rise modeling a twelve foot rise would look like this:

It is an interactive graphic, this is half of each

And original:

It is built on limestone so you can’t keep out the sea with a sea wall. However the sea is tidal of course. This is only for the very highest tides. Either storm surges or a King tide.

This is for the new “Extreme” level of sea level rise added by NOAA to its projections in 2017, corresponding to the unlikely but now increasingly plausible possibility that some parts of the Antarctic ice sheet may begin to collapse much sooner than scientists previously thought. It would mean a faster sea level rise, by 8 feet by 2100 or a bit over an inch a year. Currently it is rising at about a tenth of an inch a year. But this is for "Business as usual" and we are well below that. More details here

As for climate migrants more gnerally, the World Bank Group report in 2018 Groundswell: Preparing for Internal Climate Migration predicts that just over 143 million in Sub-Saharan Africa, South Asia, and Latin America, just over 2.8 percent of their population, could be forced to move within their own countries by 2050 in that worst case scenario. That's around 86 million in Sub-Saharan Africa, 40 million in South Asia, and 17 million in Latin America would move. They would migrate from less viable areas with lower water availability and crop productivity and from areas affected by rising sea level and storm surges.

In their best case (2 C by 2100) then around 31 million have to migrate by 2050. They also did detailed case studies for Mexico, Ethiopia and Bangladesh.

NO RISK OF HUMAN EXTINCTION WHATSOEVER

This is one of the main themes of Spratt and Dunlop's report, that we risk near term permanent degradation of the habitability of Earth or total extinction. Actually, there is nothing remotely like extinction or end of civilization in the IPCC’s example worst case climate change scenario. We are classified as of least concern by the IUCN. We have increasing numbers and are a species with many habitats we can survive in.

Pic by Neil Palmer (CIAT). A rice farmer in Kantuta, near Caranavi, BoliviaOur natural habitats include: "Grassland, Artificial/Terrestrial, Forest, Shrubland, Desert, Rocky areas (eg. inland cliffs, mountain peaks), Savanna".

I have used the entry for humans in The IUCN Red List of Threatened Species and added a photo of a rice farmer to it.

You get people doing statistical arguments that e.g. a certain percentage of mammals go extinct every century. There is just so much variability. Some species only last a short time, some last for millions of years.

Some species are living fossils and survive for a hundred million years or more. Who is to say we aren't going to be a living fossil?

Many others don't go extinct, they just evolve into new species. That of course is true of all our ancestors, right back to the origins of life itself.

550 million years ago we may have looked something like this:

Acorn worms - a living fossil, 70% of our genes can be traced back to them according to one study. Our Closest Wormy Cousins

Our half billion year old wormy ancestors didn’t go extinct. They diversified and some of them evolved into us.

160 million years ago we may have looked something like this, a mouse / rat like tiny creature that could also climb trees:

Aegyptopithecus - Wikipedia

See also

(Wikipedia is often variable in quality but that page seems reasonable).

Later we evolved through many hominids through to Homo Erectus which evolved into us. We are numerically the most successful of all the present day great apes, and the only surviving hominid, which suggests that we continue to be survivors, and our most likely future fate is that we will evolve into another species of hominid.

(click to watch on Youtube)

After all, we are evolved from survivors of the Chicxulub impactor that made the dinosaurs extinct. We are generalists and can live almost anywhere, omnivores, can eat grains, fruit, nuts, insects, shellfish, animals, birds, there isn’t that much that we can’t eat, and we can also cultivate crops. We can make fire, clothing, boats, with our technology we can tackle the most inhospitable conditions from the Kalahari to Greenland, and now even have outposts in Antarctica and in the vacuum of space. We are survivors!

Many other species are increasing in numbers, like us. Some are benefiting from the habitats that we provide for them. The feral or town pigeon for instance originated as a cliff dwelling bird. It is still a cliff dweller, but dwelling on our buildings as a kind of surrogate cliff. Without us, its habitat would be far more limited. Inheritors of the Earth: An interview with Chris D. Thomas - Hoopoe - A blog by nhbs

At present 27% of our species have at least a small risk of future extinction according to the IUCN. However, at risk here doesn’t mean that they will go extinct. Most at risk are the ones with tiny populations, a restricted range, and only small numbers of individuals. However, many of those with smaller populations, though classified as vulnerable by the IUCN, are stable. Some are extinct in the wild but survive in captivity, such as the golden frog, ready to return to the wild once we find a solution to the infection that killed the small wild population.

Many have already been saved from extinction due to conservation efforts. For instance the Giant Panda in 2016 was moved from Endangered down to vulnerable

Sheilalau, public domain.”Good news for Giant Panda, Tibetan Antelope in updated IUCN Red List.

The humpback whale is another example, moved from vulnerable to least concern in 2008.

(click to watch on Youtube)

This magnificent creature will still be here for our generations grandchildren, and this is entirely due to conservation action

Humpback whale on road to recovery, reveals IUCN Red List

There are many such examples. Indeed although some sub populations are at risk, the great whales for the most part are doing fine and increasing in numbers as a result of the end of hunting and conservation numbers. They are often misreported, for instance the recent beachings of grey whales in California were small numbers in a population that has probably already reached close to the carrying capacity for that migration route:

The IPBES report earlier this year was widely misreported. It was only talking about “threatened” species, the number of a million species included microscopic sea creatures and insects, and their message was that we can save them. Their central message was “Make biodiversity great again” - repeated in various ways throughout the press conference. That we know how to do this. They explained how to do it, with a special focus on doing something about the perverse subsidies that encourage non sustainable agriculture.

See also

In short, not only are we safe from extinction this century, we are also making sure that numerous other species are saved too, that would otherwise go extinct. Moreover, in the IPBES report we have a roadmap that can let us preserve biodiversity while increasing prosperity. Our population is predicted to level off by 2100, perhaps as soon as 2050, due to prosperity rather than resource scarcity (for details see We can feed everyone through to 2100 and beyond)..

Our civilization is not going to end either. It is interconnected but distributed. The internet is designed to function continuously through nuclear war. We have widespread literacy. If books survive, teachers survive then our civilization survives. North Korea builds skyscrapers, and can launch satellites in economic conditions  harsher than our global worst case for 2100. In worst case it might not be pretty but our civilization is nowhere near as fragile as people make it out to be. The main risk is that, say, US loses dominance, and another country, maybe a surprising outlier, Nigeria, or South Korea, or who knows, perhaps Costa Rica emerges as the new leader of civilization. UK used to be head of an empire that spanned the world, civilization continued.

Nuclear winter is pretty much disproved, - after Kuwaiti oil fires didn't cool, Sagan and many others agreed. Toon et al's model preloads the upper atmosphere with teragrams of soot, with no explanation of how it gets there. The new model to explore fires finds it doesn't. See my nuclear winter and radioactive fallout myths.

Oxygen in the atmosphere and ocean are not an issue. The residence time of oxygen is 3000 to 10,000 years. There is no possibility of running out of oxygen due to anything we do to plants. Also, though global oxygen levels in the oceans are falling, it's not due to changing atmospheric levels. The main issue is that cold water is able to dissolve more oxygen. The highest oxygen levels are in polar regions. Oxygen demanding species are migrating poleward, for instance, a 2019 study using foraminifera finds that the average community of plankton has shifted 602 km poleward since pre-industrial times (varies between 45 and 2,557 km depending on sea surface temperature change), There is less mixing of oxygen rich surface waters with deeper water in a warmer ocean. But this also has winners as well as losers, For instance larger organisms such as diatoms are likely to be stimulated by the elevated CO2 and light levels while the warmer oceans and depleted nutrients would favour smaller organisms such as the cyanobacteria. See Natural Variability and Anthropogenic Trends in the Ocean Carbon Sink. =

JAMES HANSEN - A GOOD CLIMATE SCIENTIST BUT ALSO KNOWN FOR HIS EXAGGERATED SCENARIOS IN HIS POPULAR BOOK

Spratt and Dunlop’s report also draws heavily on James Hansen who is a genuine climate scientists but does very exaggerated scenarios,

He is the one who wrote in a popular book “Storms of my Grandchildren

“After the ice has gone, would the Earth proceed to the Venus syndrome, a runaway greenhouse effect that would destroy all life on the planet, perhaps permanently? While that is difficult to say based on present information, I’ve come to conclude that if we burn all reserves of oil, gas, and coal, there is a substantial chance we will initiate the runaway greenhouse. If we also burn the tar sands and tar shale, I believe the Venus syndrome is a dead certainty”

He had no careful research to support this statement. Other scientists were skeptical right away, for instance, as quoted by National Geographic, Raymond Pierrehumbert of the University of Chicago said

"If we were going to run away, we'd probably have done it during the PETM."

See: Will Earth's Ocean Boil Away?

His idea was soon disproved. I go into that in my

His old edition of the book with the Venus prediction is still available for sale, published in 2011. There may well be readers buy it today who think that his Venus prediction is valid.

He has made many other exaggerated statements like that. His scientific research is fine but his popular writings need to be treated with some caution because of this tendency to exaggerate and say things that are speculative and not well supported by scientific research.

DAVID WALLACE WELLS - JUST A GENERALIST JOURNALIST WHO FIRST GOT INTERESTED IN CLIMATE CHANGE ONE - TWO YEARS AGO

Spratt and Dunlop also use David Wallace Wells as a source. He is not a climate scientist either. He refers to himself as a “general interest journalist”. In his Ask Me Anything (AMA) on Reddit he says

"A year or two ago, just as a general interest journalist, I began collecting stories of climate change, as a sideline interest in the news from science and technology grew into a kind of obsession."

This is not a reliable source.

Example review of David Wallace Wells:

Richard Betts, Professor, Met Office Hadley Centre & University of Exeter:

“While it is clear that ongoing warming of the global climate would eventually have very severe consequences, the concept of the Earth becoming uninhabitable within anywhere near the timescales suggested in the article is pure hyperbole. The author has clearly done very extensive research and addresses a number of climate threats that are indeed major issues, but generally the narrative ramps up the threat to go beyond the level that is supported by science.”

That book in turn is based on the Clathrate Gun hypothesis. This is now effectively disproved by the latest reviews of the USGS, Royal Society and the CAGE research, so we can ignore that as a delayed effect.

For more about this see

NEWS SOURCES THAT DO NO PRELIMINARY VETTING OF SCIENCE NEWS

Many news sources are running news about this report as if it was a new result when it is just a retelling by two businessmen of research some of it exaggerated already, and much of which they didn’t understand, to which they often added an extra sensationalist twist.

I shared a google snapshot of some of the many news sources that are running this report as if it was new science of the highest quality.

Here is how it seems in a normal web search:

The title of the sensationalist article in the Sun is almost indistinguishable from the supposedly respectable news sources like CNN

None of them, as far as I can see, even mention that the report is not peer reviewed. That no scientists have looked it over to see if there are mistakes in it (of which there are dozens).

I’m glad to see that so far at least NY Times, Washington Post, BBC and a few other respected outlets are not running this story. But disappointed to see CNN and the Independent running it.

Anyone who runs this story without explaining the nature of it to you clearly have no filter in place to check if their science news is peer reviewed or reliable.

CLAIM OF SCIENTIFIC RETICENCE

They cite a controversial paper that claimed that the IPCC erred in the direction of least drama.

You need to think of these papers like a conversation. If a paper is published it doesn’t mean it is “right” it means that someone has a sufficiently well argued point of view to pass peer review as something that other scientists will read with their coffee in the morning and then discuss.

And discuss it they did. Here for instance is part of a twitter conversation:

The same holds true of biases in simulation of extreme precipitation and long-term climate sensitivity. I think you’re right, this would be better phrased as “climate science” than “climate scientists”!

— Katharine Hayhoe (@KHayhoe) February 9, 2019

The IPCC doesn’t do any research itself. It’s a review body, reviews the research at the highest level. As those researchers tweeted, they do not bias their research towards conservative conclusions at all. They do not bias it in any direction, they go wherever their data, models, and science leads them.

Nor can the governments do this. The governments do have a major hand in the summary for policy makers. This is indeed scrutinized line by line by the governments worldwide as a final stage, but only to ensure that the report has been summarized accurately for the general public. They do not rewrite the report itself. This is done at the end after the report has been finished by the scientists,

There are three stages, first the experts review the entire report, then experts together with the governments, and the final stage focuses only on the Overview chapter.

The governments are involved to make sure that the overview chapter is

"is accurate, well balanced and presents the findings of the underlying report clearly."

It is most helpful for non scientists anyway and won’t make much difference to those interested in the background science who will probably focus on the main report. It does also give you an index into the rest of the report helping you to find relevant material - they give the chapter headings and sections in the overview so you can then go to the sections written by the scientists in the original report to check what it is they are summarizing.

For the scientifically literate reader anyway, it is often more helpful to start with the technical summary rather than the summary for policy makers. This is written by scientists for scientists.

The IPCC do not do any research themselves. Rather they are a review body that looks over the climate change literature of the last several years , and scrutinize it carefully, assessing things not just by the number of studies but their scientific merit and the amount of certainty in their conclusions. They are widely respected by the climate scientists.

EXAMPLE OF ARCTIC MELTING

The reason the Arctic melting was under-estimated was not because scientists nudged the models in the direction they wanted or discarded the ones that give higher projections. It was much simpler. It was because of issues of resolution and physics.

The climate models are computationally very expensive. They run slowly even on supercomputers if you do them at the highest resolution, so they use lower resolutions just in order to be able to run them at all. But this can lead to systematic errors if there are small scale processes that they leave out. They can compensate for this, but sometimes they get that compensation wrong.

It could as easily have been an under-estimate as an over-estimate due to some systematic issue. The whole thing is neutral as regards over or under estimating.

Then there are some things the IPCC just do not review. The reason is not because they ignore them, it’s because there isn’t sufficient research yet. Because they do not do any research themselves, that means, they can only review things that are already studied.

EXAMPLE OF SEA LEVEL RISE

This is how Spratt and Dunlop put it:

In one example, the IPCC’s​ Fifth Assessment Report in 2014 projected a sea-level rise of 0.55-0.82 metre by 2100, but said “levels above the likely range cannot be reliably evaluated”.

That is true. In the 2013 report there wasn’t enough research to properly asses the motion of glaciers in Greenland and West Antarctica. It is just hard to model.

However they didn’t ignore the problem. They stated it clearly, saying the science wasn’t there yet to evaluate it and warning policy makers to allow for higher levels than their estimates for this reason.

In the 2018 paper however, chapter 3.3.9, they say that there has been significant progress since the IPCC AR5 report in 2013. There are now many papers that do detailed sea level modeling also taking account of glaciers. So they were able to summarize these.

They were not able to come to a conclusion of the exact amount, as there was little consensus between the studies but there were studies to review, and they could give a range of the values for future sea level rise in the now extensive literature on sea level rise modeling, as well as other ways to estimate it.

At 2°C then they report that it is likely to be between 0.24 and 1.17 meters at 17 - 84% confidence, and between 0.24 and 1.17 meters at 5 - 95% confidence.

That’s a huge range. Anything between less than a quarter of a meter rise by 2100 and over 1 meter. However - that is what the literature says and their job is simply to summarize what it says.

You can read what they say in Chapter 3 of the report, section 3.3.9 Sea Level, page 206. This is what they said:

“There is little consensus between the reported ranges of GMSL rise (Table 3.1). Projections vary in the range 0.26–0.77 m and 0.35–0.93 m for 1.5°C and 2°C respectively for the 17–84% confidence interval (0.20–0.99 m and 0.24–1.17 m for the 5–95% confidence interval).

So we now have values from the IPCC for sea level rise for 1.5°C and 2°C.

However in this report, they do not cover a 3°C rise. We will have to wait for the next IPCC report for that which will be finalized in 2022.

Spratt and Dunlop go on to say

By way of comparison, the higher of two Department of Defence Scenarios is a two-metre rise by 2100, and the“extreme”scenario developed by a number of US government agencies is 2.5 metres by 2100..

Yes that is true, the NOAA report published in 2017 gives us an idea, it’s new “Extreme level” is 2.5 meters, that is for “business as usual” or RCP 8.5, lower range 0.3 meters. For a 2°C rise they have a range of 0.2 to 0.5 meters,

What they omit to say is that the reason the NOAA was able to do this while the IPCC in 2013 did not, is because it was published four years after the 2013 report. It is not because the IPCC were more cautious than the NOAA. It is because the NOAA had the benefit of four more years of research during which the field has advanced hugely. The next IPCC report will have even better estimates than were available to the NOAA.

It seems that there is no real evidence for a systematic bias here. No reluctance of scientists to consider extreme scenarios. What we have instead are just scientific limitations that are gradually getting overcome.

EXAMPLE OF “ACCELERATING TEMPERATURE RISE”

Another paper Spratt and Dunlop use in that section as a supposed example of the conservatism of the IPCC is this one:

Another example is the recent IPCC 1.5°C report which projected that warming would continue at the current rate of~1.5°C per decade and reach the 1.5°C mark around 2040. however the 1.5°C mark is likely to be passed in half that time, around 2030, and the 2C boundary around 2045, due to accelerating anthropogenenic emissions, decreased aerosol loading, and changing ocean circulation conditions.

You need a bit of background to understand this. You may get the impression that Nature only does papers that are the result of years of work, careful research, every sentence multiply cited and research that is so excellent and so carefully done that it is often thought of as just “true” because it is in Nature. If you have got your research published there you have pretty much convinced the world it is correct.

Well, sort of, but not really.

NATURE “POSITION PAPERS”

Nature also has “position papers”. These are by highly regarded professors and such-like, not your newbie PhD student with their first paper in Nature.

Here is an example, a very controversial paper about Mars, in which the authors claimed that we are “overprotecting” it and should send dirty spacecraft to Mars. This was topical at the time because Curiosity was exploring not far away from a possible salty seep that might have extant Martian life in it. Some scientists wanted it to go up and take a look. However, we do not want to confuse the issue by introducing Earth life into its habitat, and Curiosity is not sufficiently sterilized for this job. Others were saying we shouldn’t do this, and this debate then was published in nature with two position papers for the two sides of the debate. This is the “let’s send dirty spacecraft” one.

"Planetary protection policies aim to guard Solar System bodies from biological contamination from spacecraft. Costly efforts to sterilize Mars spacecraft need to be re-evaluated, as they are unnecessarily inhibiting a more ambitious agenda to search for extant life on Mars."

The overprotection of Mars

A month later the then current and the previous NASA planetary protection officers did a strongly worded response saying we need to continue to protect Mars from Earth microbes, this is the “let’s continue to sterilize” one:

Geological and biological processes have eliminated all but the faintest traces of our earliest ancestors on Earth. To understand the origin of life, we must investigate other planets — but we can find what we seek only if we do not contaminate them with Earth life first.

Appropriate protection of Mars

Each set of authors here is saying that the others are flat out wrong.

The planetary protection officers prevailed, and Curiosity did not visit this potential habitat but gave it a wide berth. However the debate continued to 2019, in another prestigious journal, the Astrobiology journal. They found no common ground, and remain as polarized as they were to start with, with passions running high on both sides - in a polite academic way of course.

I cover this debate briefly here in my astrobiology wiki, in a section of the Planetary Protection article:

THIS IS A SIMILAR “POSITION PAPER” ON CLIMATE CHANGE

This is another paper of that type. It is not even a normal Nature paper, like those two. It is a “Nature comment” with only 11 sources, most Nature papers have about that many cites to each paragraph!

Their three main points are:

  • that our emissions are increasing and that this is an “accelerating” increase,
  • that the aerosols masking effect is larger than the IPCC thought
  • That the Interdecadal Pacific Oscillation is going to lead to a higher temperature than the IPCC expected.

First, on the “accelerating increase”:

This is about the increase in 2017 they describe. More than half is due to China + India.

This is the Carbon Brief analysis (they are pretty good)

When you look at why this happened, it is not a long term trend. China are very strongly pushing renewables. Meanwhile they are having difficulty in getting some of the regions in China to stop making new coal fired power stations.

They are expected to achieve their pledge to peak emissions before 2030. It is more a matter of how fast this happens. As one of the most impacted countries, and with the ability through their more authoritarian government to get things done then they are likely to do a lot.

They already have the largest renewables industry in the world, and they are supplying solar panels to the rest of Asia at very low cost, they have huge solar farms, they have several thousand kilometer long HVDC cables to transmit renewable energy to their cities, they have grown vast forests to offset CO2 emissions.

China are doing some of the most vigorous carbon offsetting in the world, but they are also rapidly industrializing. Because they are quite wealthy now, they do not get international assistance from the green climate fund

This is not gong to stop. Their current target is 20% renewables by 2030, and they can do this easily. There were news stories recently with leaks about a possible near future increase of this to a target of 35% renewables by 2030.

It is not at all a sign of reduced effort to decrease emissions. China are so committed to renewables, that it is a question of when rather than if. The main question here is:

“As China industrializes, when will renewables in China replace enough coal based power for emissions to peak?”

Did they peak last year or will it not peak until close to 2030? So far nobody knows though it seems at least possible that China peaked last year or is close to its peak. There is a lot of confidence that China will achieve its aim to peak emissions before 2030.

They do not even mention this as far as I can tell but they must know it. It is like that Nature paper about dirty spacecraft - they presented only one side missed out lots of stuff that would basically undermine what they said and presented only one side. Both sides did that in that argument and this is similar.

There is nothing deceptive here. Any readers who follow Nature, their intended audience of science researchers, will recognize these papers and comments for what they are. You get this in all fields of science. The insight comes from the clash of the ideas, and they are not expected to give both points of view, any more than a politician in the PM questions in the UK houses of parliament would be expected to give the PM’s point of view in their witty and pointed questions they fire at her.

ACCELERATED WARMING

In this next graph the Nature authors share, red is "business as usual" and they are saying that the emissions are currently tracking BAU only on the basis of the last two years of emissions. You are asked to look at the red and the black line and see which we are on.

But if you look at it, it's not at all convincing that the pink wiggly line is following the red curve. The last point in the pink wiggly line happens to be on the red line. But a few measurements back it was below the black line and was below it for some time.

This is not hard evidence at all. In the modeling, all the emission scenarios are basically indistinguishable through to 2030.

WHAT ABOUT THE AEROSOLS?

On the aerosols, then the IPCC reviewed many articles on the topic. They were not able to decide if our aerosols are warming or cooling.

The SO2 has a cooling effect while soot and other black organic compounds have a warming effect. The aerosols also don’t decrease to zero when you stop burning coal, but rather, a gradual reduction.

Meanwhile nitrate aerosols, resulting from ammonia emissions also have a cooling effect. If the ammonia continues to rise while the SO2 is phased out, this could offset the warming effect of phasing out SO2 (page 103 of chapter 2).

Then, if there is a lot of resident biomass (e.g. wood burning) in low emission pathways, then that could increase the SO2 aerosols and have a cooling effect (page 118)

The amount of the cooling effect due to SO2 is also not well understood, depending on how the aerosols interact with the clouds.

This is very hard to study because the SO2 emissions are not well mixed in the atmosphere like the CO2 but rather is geographically patchy (and much of it is out at sea too).

With all these caveats, the IPCC best guess is that if we were to stop all emissions instantly, it's a 0.15 °C bump lasting for 20 years.

Global Warming of 1.5 ºC - chapter 1, figure 1.5

If we stop all aerosol emissions, yellow line, there is a short term bump in temperature by 0.15 degrees, and returning to the previous temperatures in 20 years and ending with a reduction to 0.25 °C below the present by 2100

However if we do sharp reductions in methane and soot, those would offset that bump.

This shows the sharp reductions in methane and soot needed for the 1.5 °C path:

This is both good for health and also has a cooling effect which is indeed offset to start with by the warming effect of removing the masking sulfur dioxide aerosols.

One way to tackle this would be to selectively reduce the black carbon (soot) emissions first by doing a targeted drive on reducing these emissions worldwide.

There may be a “baked in” warming, but if so, it is likely to be less than half a degree.

You can download the chapters from this page: Download Chapters

From chapter 1 Executive summary

Past emissions alone are unlikely to raise global-mean temperature to 1.5°C above pre-industrial levels (medium confidence), but past emissions do commit to other changes, such as further sea level rise (high confidence). If all anthropogenic emissions (including aerosol-related) were reduced to zero immediately, any further warming beyond the 1°C already experienced would likely be less than 0.5°C over the next two to three decades (high confidence), and likely less than 0.5°C on a century time scale (medium confidence), due to the opposing effects of different climate processes and drivers. A warming greater than 1.5°C is therefore not geophysically unavoidable: whether it will occur depends on future rates of emission reductions. (page 51)

This is very hard to study, there may even be no effect. From Chapter 2.2.1.1 Geophysical uncertainties: non-CO2 forcing agents

The total aerosol effective radiative forcing change in stringent mitigation pathways is expected to be dominated by the effects from the phase-out of SO2, although the magnitude of this aerosol-warming depends on how much of the present-day aerosol cooling is attributable to SO2, particularly the cooling associated with aerosol–cloud interaction (page 101)

In response to all that analysis in the IPCC report, this Nature paper provides a single cite, that says there would be a 0.7 degree offset from removing the SO2 aerosols. Their cite for this figure is an article on the effect of aerosols on reducing the water vapour content of the air.

The linked to paper is here, Global warming without global mean precipitation increase?

I can’t actually see that 0.7 C figure, either in the paper or in the supplementary materials. They just say: “On the one hand, it is well understood that the effect of anthropogenic aerosol is net cooling and drying, that aerosol cooling has reduced the overall anthropogenic warming (6–8), and that a reduction in solar radiation yields a stronger hydrological response than GHG warming (9, 10).”

Can anyone else here see the 0.7 C figure in the paper or supplementary material?

In any case, whatever they say, it is only one cite, and it precedes the IPCC review, so they must have read it.

Also if there is a masking effect from anthropogenic emissions, it is a one-off thing not really an acceleration of warming.

WHAT ABOUT THE INTERDECADAL PACIFIC OSCILLATION?

The natural warm phase argument about the Pacific interdecadal oscillation - that's not about permanent increases in temperature. There is always a lot of fluctuation around the curve whatever you are on They are saying we may be in a fluctuation upwards by 2030 and briefly hit i1.5°C. So what? That means later in the 2030s it will be a fluctuation down. The IPCC allows for this. In their graph, the 1.5°C path actually could reach 1.5°C as early as 2030, just as this paper is suggesting.

This answer would run to many dozens more pages if I were to answer everything in this report, but hopefully that gives a taste of why it is not something to take seriously, as well as maybe giving interesting sidelines on some of the topics often discussed in this topic area.

So in short - this paper is not evidence that the IPCC are conservative in their estimates of warming effects. And it is not actually even evidence that they underestimated the effects of global warming under the pathway we are on.

It is a controversial Nature comment, based on only a few cites. Whether they have a point here or not is something that may be discovered in future discussions and comments in Nature.

TIPPING POINTS TO A HOTHOUSE EARTH

Spratt and Dunlop write in their report:

Recently, attention has been given to a ‘hothouse Earth’ scenario, in which system feedbacks and their mutual interaction could drive the Earth System climate to a point of no return, whereby further warming would become self-sustaining (without further human perturbations). This ‘hothouse Earth’ planetary threshold could exist at a temperature rise as low as 2°C, possibly even in the 1.5°C-2°C range.

They are referring there to the “Hothouse Earth” paper published last year. It was widely misreported.

This paper was mainly about things that could happen centuries to thousands of years into the future. It didn't conflict with the IPCC who have already concluded that these tipping points may have significant effects before 2100 but that these effects are minor.

For instance the permafrost is already melting and at the temperature rise we already reached, it should continue to melt for centuries. But only slowly.

For another example, the Greenland ice sheet has started to melt, and Western Antarctica glaciers are on the move, though the Eastern Antarctic is still accumulating snow.

The IPCC in the 2018 report write:

There is high confidence that sea level rise will continue beyond 2100. Instabilities exist for both the Greenland and Antarctic ice sheets, which could result in multi-meter rises in sea level on time scales of century to millennia. There is medium confidence that these instabilities could be triggered at around 1.5°C to 2°C of global warming.
technical summary (page 11)

The authors of the “HotHouse Earth” paper talk about three scenarios, the Hothouse Earth, "Stabilized Earth" and "Glacial Interglacial cycle". We have already moved out of the last of those - we have probably done enough already to avert any future ice ages. So that's actually good.

So the remaining options are the "stabilized Earth" where for hundreds of thousands of years Earth just stays stable, and "Hothouse Earth" where it goes looping around to some very hot state and then back to where it is now.

They say that we should aim for the "Stabilized Earth" and they think that these tipping points mean that if we don't take the opportunity right now it will be much harder for people later on to make that choice. I.e. that there are things we can do in the next decade or two that will make life much easier for our descendants.

It is an idea however and not proved, it is a suggestion for other researchers to follow up to see if what they suggest is right. And whatever the outcome of that discussion it is not relevant to 2050 or even 2100.

I could go on. But to do that would make this far longer than the original report.

SUMMARY - DO NOT USE THIS REPORT

This is not a reliable source on this topic. You should not use it. Some of the sources they use are indeed reliable, but are misrepresented or misunderstood.

The best source by far is the IPCC. They do the highest level of review. They are not conservative; they reflect the current understanding of scientists and the full range of views.

But we are not headed there as there has been a lot of action in the last three years and it is remarkable what we are doing already, with much more sure to come with the increasing green awareness of the young generation. They will grow up to be the next generations voters and politicians in the twenties and thirties.

The young children doing “School striking” around the world today are tomorrow’s voters and politicians.

Greta Thunberg at the EU Parliament

I discuss the example from the 2018 report here,

It’s from their chapter 3 which is written by scientists for scientists. This is a far better starting point for discussing what the worst case is for 2050.

WHY I WROTE THIS

I spend hours every day, typing at my keyboard sometimes from when I wake up nearly all the time until I go to bed helping really scared petrified people who have come to believe that they, or their children will not grow to adulthood or will be attempting to survive in a basically uninhabitable desert by the second half of this century or even within a decade. It is so far from the truth, and they are not galvanized into action by these stories, they are paralyses with fear, often receiving medical help with drugs and therapy to deal with their terror, vomiting with fear, crying all day, neglecting their jobs and studies. I do not think we should ignore these people and I for one can't do it. They are my top priority.

It most affects children and young adults - the ones who lead the Extinction rebellion, the equivalent of Greta Thunberg who didn't speak for a year but came through it. These ones are still stuck in that space of terror and panic. Also young parents who are concerned for their children.

I think telling the truth here, neither catstrophist or denialist, just the plain truth, is the way ahead. And part of that has to be counteracting catastrophism because it just fills the news ever since last autumn and particularly this spring, it is just full of this NONSENSE.

GREAT PROMISE FOR THE FUTURE

We are acting together on these issues in a way that is already remarkable. We can continue to do this.

When I see the school striking children and the climate activists, I see great hope for the future. They are the ones who will be voting for new initiatives and decisions in the 20s and 30s. They also include our future politicians; some may be future presidents of the great countries in the world, and world leaders.

As time goes on and the effects of climate change become more and more obvious, surely these children as they grow to adulthood are going to be more motivated to work on it, not less. Surely we are headed to a world where more is done about climate change, not less.

(click to watch on Youtube)

One of the largest environmental protests ever is underway. It’s led by children.

We have already done so much in other areas e.g. conserved the great whales, completely stopped hunting, prevented starvation with the green revolution, and acted to stop the deterioration of the ozone layer and many other things.

We can stay within 1.5°C. The EU is close to it, and especially with the green wave elections, likely headed that way some time in the next few years.

India has this well within reach, mainly because it has such low per capita CO2 emissions already. It will help if it gets more international assistance to let it prioritize renewables more. The plummeting prices of solar panels should help too, a near certainty but one that can’t be assumed in climate pledges. China needs to increase its pledges hugely to stay within 1.5°C but it is headed in the right direction and has ten years to do this for the easiest way to stay within 1.5°C.

As for the US, they need to come on board some time before 2030 for the easiest way to stay within 1.5°C. However, the US CO2 emissions have already plateaued. Renewables are increasing there because they are able to compete economically with coal, and much of the US is already on board with the goals of the Paris agreement, including California, which would count as the world’s fifth largest economy if it was a separate country. California has already committed itself to produce 60% renewables by 2030 and all electricity from carbon-free sources by 2045

The US is not going to be far off meeting its original Paris pledges even without government support. In the future, with increasing evidence of climate change, even if all the presidents are like Trump, surely by Trump 3 or Trump 4 in 2030 then they re-engage on this matter, as the population of the US notices the effects more and more.

The UK parliament declared a "Climate emergency". Scotland is in process of committing to zero emissions by 2045. Joe Biden, one of the front runners for Democrat nomination for 2020 has committed to zero emissions for the US by 2050 if he is elected. Next in the polls is Bernie Sanders who supports the very ambitious green new deal, to convert the US to 100% renewables for electricity within a decade. Whoever the Democrat nominee is, it's a near certainty they have an ambitious climate pledge for 2020. Whoever wins the 2020 election, climate change is going to be firmly part of the election campaigns in 2010, and was barely touched on in 2016. US emissions are more or less level and they have until 2030 to commit to a more ambitious pledge for the easiest path to 1.5° C and many states, private companies, and cities are already committed to the Paris agreement in the US. The US has two more presidential elections after 2020 before 2030, plenty of time to elect a president who commits to this target, as the effects of climate change on the US become increasingly more noticeable.

The EU Green Wave is a new force in politics that is hard to ignore and has a good chance to push the EU towards a Europe wide 1.5 C compatible policies.

China, largest CO2 emitter, is expected to increase its 2030 pledge from 20% to 35% renewables for electricity. India is overachieving its target to keep the increase well below 2 C. Although its CO2 emissions are projected to continue to rise for a while in the near future, it starts with a far lower baseline of half a ton per capita.

As the Paris agreement process continues it is definitely possible that the world as a whole has 1.5°C compatible pledges by 2030 . We can do this with the technology we already have, is politically feasible, and makes economic sense too.

As for what you can do individually, there are many things you can do, and probably are already doing. However one thing that few of us think of that makes a huge difference is to reduce food waste. In the developed world especially much of our food is wasted. That’s especially important for meat, even though only 20% is wasted, so much land is used for livestock, that it corresponds to 20% of the area of the Americas that is used for livestock that isn’t eaten but is wasted on the consumer’s plate. Reducing food waste is a simple way to help with both climate change and biodiversity.

We can do this!

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