Donald Trump has just been elected as US president, as a Republican climate skeptic. So if you are from the US you may get the impression that this is a political debate between “lefties” who think climate change is real and “righties” who think it isn’t. But it’s only in the US that there still is a political debate at all. Here in the UK for instance it has cross party support, and we have a right wing government who have just ratified the treaty. For us, it was a matter for debate a decade or two ago, but the debate was already over some years back. We've decided action is needed, and there were many things we could have done, but the main thing was to do something, and the Paris agreement was what they came up with.

Boris Johnson, foreign secretary and right wing politician in the UK signing the document to ratify the Paris agreement. UK signs up for Paris climate agreement. The agreement has cross party support of all the major parties here. It was put before both houses (House of Parliament and House of Lords) for scrutiny, and no objections were raised.

We do have a few climate skeptic MP's here still, but MP Peter Lilley told BBC News he didn’t object because he didn’t notice it, he could have got a few names together but it would have been a rather ineffective gesture.

That’s true world wide also, it has support from governments of all political persuasions, unless you think Saudi Arabia, and Iran have left wing governments!

It also has support from the most capitalist countries as well as the most communist ones. This is the 2015 list of the most "economically free" countries.  in the Economic Freedom of the World (EFW) annual survey by the Fraser Institute

They say 

"The cornerstones of economic freedom are personal choice, voluntary exchange, freedom to enter markets and compete, and security of the person and privately owned property" 

which sounds pretty much like the basics of capitalism. So they say that the ten most economically free countries are 

"Hong Kong and Singapore, once again, occupy the top two positions. The other nations in the top 10 are New Zealand, Switzerland, United Arab Emirates, Mauritius, Jordan, Ireland, Canada, and the United Kingdom and Chile, tied for 10th."

Of those, all except Ireland and Hong Kong have already ratified the treaty.

This site is also useful, tracks the countries and rates them according to whether their actions are inadequate, medium, or sufficient. Since Trump has claimed it is all a plot by China, let’s look at what they are doing: China - Climate Action Tracker

As you can see, they are one of the countries doing a fair bit to deal with climate change. China is set to peak CO2 emissions between 2025 and 2030. That's not yet sufficient to achieve the target of 2 °C by 2100, but they are keeping well within their pledges for the treaty. As with most countries they have to work harder to get down to 2 °C and even more to target 1.5 °C and so we hope they will make more pledges as the process continues.

This shows their reduction in CO2 intensity (this is not the same as emissions, this is a measure of how their industry is producing less carbon dioxide for the same amount of energy production):

China’s Climate Policies: How Have They Performed, and Where Do They Need to Go?


As you may notice in the Climate Action Tracker, the top countries in the list count also amongst the poorest. Ethiopia is top of the list, set to keep us within 2 °C by 2100.

Ethiopia - Climate Action Tracker

Although they produce only a tiny fraction of the total carbon dioxide emissions, the poorest countries are amongst the ones most affected, and they are doing their bit to reduce the very small amount of CO2 they do produce. Indeed they are amongst the ones with the most ambitious targets.

Ethiopia already aims for an unconditional 64% reduction compared to business as usual emissions by 2030, equivalent to a 3% reduction against a 2010 baseline. 85% of their emissions are from agriculture and forestry so this is their main focus. They plan to achieve this by such measures as more efficient cooking stoves, and expanding forest cover. You can read details of their emissions reduction plans and climate change mitigation measures here Intended Nationally Determined Contribution (INDC) of the Federal Democratic Republic of Ethiopia

They also plan to increase their pledges before 2020. Bangladesh, Ethiopia, Haiti and 44 other countries members of the “Climate Vulnerable Forum” have said they will update their pledges before 2020, with an aim of 100% green energy between 2030 and 2050 if they get economic and technological support to achieve those goals World's poorest countries to aim for 100% green energy - BBC News


Even in the US both right and left wing states are taking measures to combat climate change. Examples of states that are pioneers in this field include California, no surprise, but also Tennessee which has reduced emissions from electricity by 34% since 2005, and Louisiana amongst others. Details here: Trump could reverse 'dramatic' progress on clean energy, experts fear

See also this Analysis of 19 states by Georgetown Climate Center showing a “dramatic shift” to clean energy. Either from climate change concerns or economic reasons.


This is a statement by many US companies asking Trump to stay with the Paris agreement: including DuPont, Gap Inc., General Mills, Hewlett Packard, Hilton, HP., Kellogg, Levi Strauss., L'Oreal USA, NIKE, Mars, Schneider Electric, Starbucks, VF Corporation and Unilever.

365+ Businesses Call on Trump to Support Paris Climate Agreement


The Arctic is amongst the most affected by climate change - with the ocean almost ice free in recent summers. Right now as of writing this, it is 20 °C (36 °F) warmer than usual.

See that red spike to the right - that shows how much it is above normal temperatures for this time of year in the Arctic

The North Pole is an insane 36 degrees warmer than normal as winter descends

For the last four years the ice cover in the Arctic has been well below the average values for 1981 - 2010 every single year.

Figure from Arctic Sea Ice News.

For an example of the experiences of people in the Arctic, see this blog post by LEIF MAGNE HELGESEN Pastor at Svalbard island archipelago of Svalbard, closest inhabited area to the North Pole is experiencing very warm weather, rain when it should be snowing, leading to landslides as well as in this example:

Landslide near Longyearbyen kirkegår, October 2016. Photo: Leif Magne Helgesen Svalbard regner bort - Kirkens Nødhjelps blogg (I found out about it from this Washington post article Dear President Elect Trump: Climate change is no hoax

I’m in the UK and we’ve had warm wet winters and heat waves in summer. Temperatures of 30 °C in summer are not normal for us.

Islands in the Pacific are already disappearing beneath the sea. Five Pacific islands lost to rising seas as climate change hits

None inhabited yet but others have had to retreat.

World wide, glaciers are retreating, the oceans are becoming more acidic - just slightly so but enough to endanger coral reefs. This is happening already and the bleaching events are predicted to become more common. An image of a turtle swimming over bleached coral graces the cover of Australia’s coral reefs report:

Australia's Coral Reefs Under Threat From Climate Change

We are already seeing record numbers of heat waves. And this is set to continue. This graph shows how temperature anomalies have changed over the northern hemisphere - not a prediction, but a record of what has already happened.

Details from here Heat Waves: The Details


The most quoted figure is 97% of climate researchers, see Scientific consensus: Earth's climate is warming but some surveys come up with a figure of 100%.

Here is a climatologist criticizing the 97% figure as not high enough. The author says that papers written about effects of climate change, mitigation etc should be taken as endorsing unless they explicitly reject it, similarly e.g. to papers on continental drift or the impact origin of lunar craters which will only very rarely explicitly endorse the established theory. On that basis rather than 97% it's more like 99.9% or more

"Of 24,210 abstracts, only five—one in 4,842 or 0.021 percent—in my judgment explicitly rejected AGW. Two of the articles had the same author, so four authors of 69,406 rejected AGW. That is one in 17,352, or 0.0058 percent."

The Consensus on Anthropogenic Global Warming - CSI


This is something you might well ask if you have watched “cowspiracy”. However it exaggerates the situation. For a criticism of the film by the union of concerned scientists: Movie Review: There’s a Vast Cowspiracy about Climate Change.

Livestock produce 8-18% of greenhouse gas emissions according to the paper they cited, not the 51% of Cowspiracy - that is for all livestock world wide, not just beef. It's still a lot. But there is no conspiracy to hide this. It seems a very active area of research with many papers. These are the google scholar search results for 2016.

Methane has a much shorter residence time in the atmosphere than CO2. Around twelve years compared to 100 years for CO2 (however the situation for CO2 is complex, some of it is removed within 50 years, some remains for thousands of years, more on this later). For the figures see The Scientific Basis

As for CO2 from breathing, then that’s carbon neutral. Every time you eat, you convert food to CO2 which you then breathe out. However that food would have decayed anyway so you are just speeding up the process of decay. When the farmer grows the food next season all the CO2 you breathed out gets taken up again into the plants. That’s the reason for the oscillations every year in the CO2 concentrations graphs


The situation for CO2 is complex and doesn’t follow the exponential decay curve you might expect. The average lifetime of a CO2 molecule is around 4 years in the atmosphere. But that’s for the more rapid processes such as plant growth, and absorption in the surface water of the ocean. Much of that gets circulated back into the atmosphere again. The slower cycle of removal of CO2 from the atmosphere is complex and behaves in surprising ways.

For instance after adding a pulse of CO2 to the atmosphere, half is removed in 50 years. You might think, half would be removed again in the next 50 years, but no, it takes 250 years to get down to a quarter of the original concentration. Finally, around 15 percent of the original pulse remains in the atmosphere pretty much permanently, for thousands of years. CLIMATE CHANGE - the IPCC scientific assessment

So of the roughly 32 billion tons of CO2 humans added to the atmosphere in 2010

  • 16 billion tons will still be there 50 years later, in 2060,
  • 8 billion tons will still be there 250 years later in 2260
  • 4.8 billion tons will still be there indefinitely, for thousands of years.

From the Climate Change 2014 Synthesis Report Summary for Policymakers

So you have to be careful how you do the calculations.

That’s why it is important not just to stop the increase in CO2 emissions, but to dramatically reduce emissions if we want to stay within 2 °C rise by 2100, and even more so to stay within 1.5 °C. It’s also why we have to act quickly, by 2020, if we hope to remain within 1.5 °C by 2100.


This article, that the IPCC published November 2014 examined various scenarios. They concluded that to  have a reasonable chance of remaining within 1.5 °C then we have to produce no more than 6 years worth of of emissions at the current levels before 2050. So since we are still producing it at the same rate now, that means another 4 years worth of emissions is our lot before 2050 if we want to stay within 1.5 °C.

It's not an absolute. Depends what we do after that. The conclusion is 

" suggests we have just six years of business-as-usual emissions before the budget giving us a two-thirds chance of staying below 1.5 degrees is exhausted." 

So, if that is right, we have to reduce emissions drastically before 2020 to have a chance of keeping the total CO2 emissions up to 2050 the same as 4+ more years of business as usual (now that it is 2016). I.e. not just that we have to start reducing by 2020 but well before 2020 we have to reduce emissions drastically to have a decent chance of remaining within 1.5 C by 2100. The higher targets of 2 C are more easily achievable. 

That's why the poor countries are aiming for 0% emissions so quickly. They want to reach 0% emissions between 2030 and 2050. We should all try to follow suit if we want to stay within 1.5 C, to get as close as possible to zero emissions by then, since we have left it so late, 

That's why it is so urgent, if the climate models are correct. That's why so many feel we can't just sit around and discuss it and wait for climate change to become more and more obvious. For many of us, it is abundantly obvious already, not a certainty, but near enough of a certainty that we just don't want to wait some more to see if it pans out as expected. If we are going to act on it, we have to act quickly, if we want to remain within 1.5 C


A while back the models weren’t as good as they are now, perhaps a decade ago. But science has moved on a lot. Those who still criticize them. e.g. on social media often misunderstand how they work.

Yes it’s true that if you run the models with slightly different starting parameters then the weather will be completely different for, say, one year ahead. That’s because of the butterfly effect - a small change in initial conditions equivalent to a butterfly flapping its wings can make a difference between whether or not a hurricane forms months or years later.

butterfly effect by mindfulness

That's why they can't predict a hurricane the year before it happens. Surely we will never be able to do long term predictions like that accurate enough to predict the exact date of every hurricane. You can’t have sensors monitoring every flap of a wing of every butterfly in the world.

However, they can run the models lots of times with different starting conditions, varying them slightly corresponding to the uncertainty in measurement there always is - then run them for a decade, or five decades or whatever. Each run will have different results on a year to year basis, but trends emerge longer term.

If the hurricanes are more intense on average whenever it is run with the extra CO2, over time periods of several years or decades, and if it always does this, starting with many slightly different starting conditions, then that suggests that we will in fact get more intense hurricanes in the future.

To validate it they set it to predict, e.g. the current decade using data from previous decades. Then other teams will work on the problem from scratch with different modeling methods. If they all come to the same conclusions too - they have a lot of confidence that we will get more intense hurricanes in the future as the CO2 levels rise.

Incidentally it’s often said, incorrectly, that the prediction is for more hurricanes. Actually the models currently predict an increase in the intensity of hurricanes, with stronger winds and more rain. However they also predict a possible decrease in the number, so though there is less confidence in this, there may be fewer of the weaker hurricanes as well as more of the more intense ones. See Tropical Cyclones (Hurricanes and Typhoons)


This is from the 2014 IPCC report Climate change threatens irreversible and dangerous impacts, but options exist to limit its effects - UN and Climate Change

Once we achieve zero emissions, the temperature of the atmosphere will stabilize quickly but the world will remain warmer, and will not cool down back to 1950 levels. Instead, temperatures will stay at the same higher temperatures for many centuries. That is, unless we remove large amounts of CO2 from the atmosphere over a sustained period after we achieve zero emissions.

There are many longer term effects also.

The ocean warms only slowly, influenced by the warm air above it. The ice in Antarctica melts even more slowly, and those also contribute to sea level rises (any ice floating on the sea, such as the ice in the Arctic, makes no difference to the sea level when it melts, but ice on land such as the Greenland and Antarctic ice sheets will raise the sea levels when the melt). Over the long term, a thousand years into the future, the Greenland ice sheet is almost certain to vanish completely eventually if we reach 4 °C, and may vanish even at only a 1 °C rise, leading to a sea level rise of seven meters.

So the sea levels will continue to rise for a long time to come again no matter what we do. But by acting quickly we can reduce the amount of the total future rise.

Ocean acidification will continue for centuries, and strongly affect marine ecosystems.

Other risks include the possibility of abrupt and irreversible regional-scale change in the composition, structure and function of marine, terrestrial and freshwater ecosystems, including wetlands

However we shouldn’t go away with the view that this means that the Earth is going to become uninhabitable!


In the short term the worst case scenario is that the world gets 4 °C hotter by 2100, and the Paris climate change agreement measures so far will reduce the rice to 3.4 °C - all temperature rises here are relative to pre-industrial levels.

So that’s obviously not going to make it too hot for us. The main issues are due to the speed with which the climate is changing, not the final climate which may be more habitable in some ways. Earth is actually unusually cold at present. At times in the geologically recent past the world has been so hot that there were palm trees as far north as the Arctic circle, no ice at either pole and typical polar temperatures 10 °C.

Phanerozoic Climate Change

500 million years of climate change. As you can see, on the timescale of millions of years. Earth has never been this cold for the last 45o million years. In this diagram, one part per thousand of oxygen 18 corresponds to around 1.5 - 2 °C

Most of the time Earth has no ice at all at its poles, no permanent ice at all except at the top of high mountains. Compared to that, the Earth is unusually cold at present. We are in the middle of an interglacial but geologists would say we are in the middle of an ice age still, technically, since we have permanent ice at the poles.

In the worst case scenario, the world stabilizes at 7 °C hotter than pre-industrial levels many centuries into the future - assuming we have stopped creating CO2 by then.


In theory we could make the world uninhabitable by triggering a runaway greenhouse effect, but to do that we would have to burn ten times the total reserves of oil, gas and coal in the world.

The temperature rises even with no restraint on global warming aren’t nearly enough to melt Antarctica. The world will still be very habitable and on the cold side of normal if anything.

The reason that so many countries signed the climate change agreement in Paris is not to protect humans from extinction, which was never a risk. Nor is it to prevent Earth’s climate changing, which it does slowly all the time anyway.

It is because the speed of the change is going to have effects on our environment (e.g. bleaching of coral) and it’s also going to be expensive to deal with the issues later. If we act now, it doesn’t even need to impact on our standard of living. It’s a case of policy change mainly. Promoting clean energy and measures to reduce carbon dioxide. If we act later, it probably will impact on quality of living and more than that, many people will need to relocate and it will impact on the environment in various ways

It’s a case of paying a bit more now, or even maybe not paying much, just planning now, to avoid much larger costs a few decades into the future and at the same time to protect fragile environments too, which are at risk because of the speed of the change.

Even the speed of change isn’t that unusual - our climate has been relatively stable for 10,000 years so it is a fast change compared to the last few thousand years - but during the ice age between 18,000 and 180,000 years ago then it fluctuated rapidly even within a few decades. Abrupt Climate Change During the Last Ice Age

But for us, living at a time of relatively slow climate change, this is something we are not used to


Also the idea isn’t at all that global warming is something we couldn’t survive. Put enough money into it, flood defenses, growing new crops that farmers aren’t used to in their region, relocating people, building new foundations to replace the ones destroyed by melting permafrost in Alaska and Canada, building houses to withstand flood damage, more severe hurricanes, better disaster relief and so on - we can cope with it. But it would be expensive.

Rather, the idea of the climate change agreement is that it is far more expensive to respond to climate change like that - than it is to prevent it from happening in the first place which we can do mainly through policy changes. The Paris agreements might even have economic benefits too, e.g. transition to clean energy leading to new industries. The nations that work hardest on mitigating climate change, e.g. Germany, and for that matter China which is also putting a lot of finance into clean energy, are building up an industry that the rest of the world will want.

Also if we just let the temperatures rise and mitigate the effects, it has environmental effects too which can't be reversed, e.g. 99% of all corals affected by a 2 °C rise compared to 90% for 1.5 °C.


There’s a summary here: “For example, an extra 0.5 °C could see global sea levels rise 10cm more by 2100, water shortages in the Mediterranean double and tropical heatwaves last up to a month longer. The difference between 2 °C and 1.5 °C is also “likely to be decisive for the future of coral reefs”, with virtually all coral reefs at high risk of bleaching with 2C warming.”Scientists compare climate change impacts at 1.5 °C and 2 °C | Carbon Brief

There’s a summary here

Note that with 2 °C rise, instead of 1.5 °C, it’s wheat down by 16% instead of 9%. Maize down 6% instead of 3%.

Rice production however goes up 8% instead of 6% so some crops benefit from a warmer world.

It has the same figure there that we lose our chance to limit to 1.5 °C by 2020 (4.5 years from summer 20160 if we haven’t taken enough action by then.

This is about the Paris agreement, pledges so far should keep temperatures by 2100 to between 2.9 and 3.4 °C. Paris climate deal enters force as focus shifts to action - BBC News


You can look up the predicted effects of climate change on your country, also globally. Once you do that you may understand why so many nations signed the Paris Climate Change agreement.

In the US the main changes projected include:

(quoting from the US Environmental Protection Agency

report Future of Climate Change) -

  • “Summertime temperatures in the United States that ranked among the hottest 5% in 1950-1979 will occur at least 70% of the time by 2035-2064
  • “Northern areas are projected to become wetter, especially in the winter and spring. Southern areas, especially the Southwest, are projected to become drier
  • “Heavy precipitation events will likely be more frequent, even in areas where total precipitation is projected to decrease.
  • “Heavy downpours that currently occur about once every 20 years are projected to occur between twice and five times as frequently by 2100, depending on location
  • “The intensity of Atlantic hurricanes is likely to increase as the ocean warms.
  • “Cold-season storm tracks are expected to continue to shift northward. The strongest cold-season storms are projected to become stronger and more frequent
  • “Permafrost is expected to continue to thaw in northern latitudes, damaging buildings, infrastructure, and ecosystems in Alaska.

You can also look up the effects for individual states, e.g. this climate change report for Nebraska

And this is the projection for New York city which experiences higher sea level rises than the global average:

  • Projections for sea level rise in New York City are 11 to 21 inches by the 2050s, 18 to 39 inches by the 2080s, and could reach as high as 6 feet by 2100.

New York City Panel on Climate Change 2015 Report Executive Summary

Other projections include:

  • “The frequency of heat waves is projected to triple by the 2080s, and extreme cold events are projected to decrease.
  • “The frequency of extreme precipitation days is projected to increase, with approximately one and a half times more events per year possible by the 2080s compared to the current climate.”


there are some climate scientists who think the world will get hotter than most predict, and that there will be more flooding. James Hansen particularly, a US climate scientist, thinks that the Paris agreement doesn't go anything like far enough and that we still risk sea level rises of several meters over the next 50 to 150 years

He has a reputation of prescience in this area, because he predicted that the effects of climate change would become noticeable far sooner than most other researchers in a 1981 paper and he turned out to be right when more detailed models were possible, then the climate changes matched his predictions. However that doesn't mean that he is always going to be right of course, and there's a fair bit of skepticism about his new paper. See Climate guru James Hansen warns of much worse than expected sea level rise. Also Has veteran climate scientist James Hansen foretold the ‘loss of all coastal cities’ with latest study? In an earlier 2013 paper he also examined what would happen with "Business as usual" and concluded that much of Earth would go above the 35 °C limit for survival without assistance.

His work is an outlier in the field of climate research. Few scientists predict such drastic changes as this. However even with his extreme scenario, with business as usual, no climate change reduction, the colder places of course would still be inhabitable. It's not a human extinction scenario.

The "Age of Stupid" video is based on extreme predictions, and exaggerates them even further, by way of poetic license, for the sake of a good story and to get the message across. The mainstream view of what will happen is as described already above.


As for a Venus style runaway warning, we need more oil, and gas, than we have on Earth. (an earlier paper suggesting it could be done with just the reserves we have on Earth was shown to be incorrect later on). 

Titan, moon of Saturn in infrared and ultra violet, false colour image. It has lakes of liquid ethane and an atmosphere of methane and ethane. We don't have enough coal, oil, gas or shale oil on Earth to trigger a runaway greenhouse effect.

We would have to be monumentally stupid and do some space megatechnology project importing vast amounts of oil and gas from space to trigger a runaway greenhouse effect on Earth. (This is not remotely within current capabilities)

In the distant future, billions of years from now, the Earth will become too hot for humans as a natural effect of the sun getting hotter - unless whatever civilization there is around then does something to prevent it such as shading the sun with shades orbiting Earth. Alternatively, it could physically move the Earth using repeated flybys of asteroids or some other method. Both of these ways of cooling down Earth are megatechnology projects but are feasible with near future technology.

However, those timescales are so huge that humans could evolve from microscopic multicellular life consisting of a few cells many times over (the process took about half a billion years last time). It's not something we need to give thought to for hundreds of millions of years.

For more about all this see How hot could the Earth get?

In short what we are talking about here is no apocalypse. Many humans at least would survive just fine. Even with "business as usual" and even if Hansen is right with his extreme projections, the worst of the worst scenarios suggested, still large parts of the world would remain habitable to humans.But with all these projections, "Business as usual" could have severe environmental effects, and be expensive and hard to deal with.


The climate skeptics are presenting a tiny chance that perhaps all except one or two experts on climate change, 99.9% of them have got it wrong, and all the anomalous weather we have experienced is just natural variability. They are saying, that we should just take the chance on it, that they are right, and do nothing about it. It doesn’t seem a good deal to me! And just about all the other countries except the US have shown their support for vigorous action to do something about it.

If Trump continues with his policies in the US he will find himself in a small minority of one on the world stage. Meanwhile if anything his stance on climate change seems to be galvanizing the rest of the world to more action on the matter.

Trump campaigning in Las Vegas, Nevada, February 2016. Photo by Gage Skidmore. 

His rhetoric about climate change has galvanized countries into action, leading them to ratify the treaty in record time and put forward strong initiatives for the future. So paradoxically he may actually have helped with the process of climate mitigation. See also Trump: The best thing ever for climate change? (BBC).

The strong and upbeat MARRAKECH ACTION PROCLAMATION which they signed, affirms their strong commitment. They declare that they have seen an extraordinary momentum on climate change worldwide and that this momentum is irreversible, and call for further climate action and support well in advance of 2020.

Here are some extracts from it:

“Our climate is warming at an alarming and unprecedented rate and we have an urgent duty to respond

Indeed, this year, we have seen extraordinary momentum on climate change worldwide, and in many multilateral fora. This momentum is irreversible – it is being driven not only by governments, but by science, business and global action of all types at all levels

We call for urgently raising ambition and strengthening cooperation amongst ourselves to close the gap between current emissions trajectories and the pathway needed to meet the long-term temperature goals of the Paris Agreement.

We call for an increase in the volume, flow and access to finance for climate projects, alongside improved capacity and technology, including from developed to developing countries.

We the Developed Country Parties reaffirm our USD $100 billion mobilization goal.

We, unanimously, call for further climate action and support, well in advance of 2020, taking into account the specific needs and special circumstances of developing countries, the least developed countries and those particularly vulnerable to the adverse impacts of climate change.

The transition in our economies required to meet the objectives of the Paris Agreement provides a substantial positive opportunity for increased prosperity and sustainable development.

The Marrakech Conference marks an important inflection point in our commitment to bring together the whole international community to tackle one of the greatest challenges of our time.

As we now turn towards implementation and action, we reiterate our resolve to inspire solidarity, hope and opportunity for current and future generations


See also Countries unite to defy Trump climate threat - BBC News