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By Patrick Lockerby | March 10th 2010 05:05 PM | 5 comments | Print | E-mail | Track Comments
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Mother Earth Cycles To Work


Anthropogenic global warming.

AGW

Human-caused warming.

Call it what you will: is it real?

In short: can humans modify Earth's climate?

There are two major views on this question:

1 - human emissions of CO2 cause global warming.

2 - global warming is part of a natural cycle.


I suggest that neither view is sufficiently correct because the underlying suppositions and simplifications are false.

The Earth's dynamic systems are many.  They are complex in and of themselves.  They do not act in isolation, but interact amongst themselves.

Accordingly, one might ask:

"given the complexity of our planet's interacting systems: is it both possible and probable that human activities could cause a profound overall change in the global environmental system taken as a whole?"

In short: can humankind throw a spanner in Mother Earth's works?



Earth's natural cycles

Explanations abound of the carbon cycle, hydrological cycle, nitrogen cycle etc.  It is much less common to find writers trying to tie any of these together.  What about carbohydrates as linking the CO2 and the H2O cycles, to name just one idea?

The major cycle that doesn't tend to get mentioned is the Earth's entire thermodynamic cycle. 
In order to accurately model the climate one must allow for all known factors - model all known systems - and then treat their thermodynamic actions and interactions.


Within the overall system that is our natural environment one finds a large number of sub-systems.

For now, I will list only the

astro
bio
carbo
chemo
cryo
geo
hydro
meteoro
nitro
photo
thermo

cyclic systems.

Thats the Earth's entire astrobiocarbochemocryogeohydrometeoronitrophotothermocyclic system, for lovers of agglutination.

Let's briefly examine the component cyclic sub-systems.

Astrocycles - astronomical scale cyclic events that affect our environment.

Under this heading are included all natural cycles that affect how much the Earth is warmed by solar outputs.  Also included are heating effects due to both lunar and solar tides.

Biocycles - all biological cycles that affect the environment.

These cycles include the biological production / transpiration of - mainly - O2, CO2, H2O, CH4, NO3, N2O etc. and of hydrocarbons.  It is important to note that plants don't just 'lock away' carbon - they lock away water and solar heat as well.

The planetary biomass contains vast quantities of water.  This biomass has non-trivial thermal mass.  The thermal storage properties of the biomass must be allowed for in environmental models.


Carbon cycles - all non biological exchanges, storage and release of carbon.

The non-biological carbon cycle has long and short term components.  These need to be modelled separately and not just lumped together.  CO2 in air, freshwater, seawater and ice affects the environment differently.  Again, carbon in rocks, coal, oil, shales, peats, soot and other forms affects the environment in different ways and on different time-scales.

Chemocycles - chemical cycles not included under other headings.

I give a simple example here.  Runoff of rain from land enters the rivers, lakes and oceans.  It flushes nutrients from soil and carries dissolved chemicals from rocks.  It is the primary cause of ocean salinity.  Over geological time, some bodies of water dry up, leaving chemicals on land.  In broad terms, there is a cycle controlling ocean salinity and other chemical content.

Cryocycles - cycles of ice and snow formation and melting.

The precipitation that adds to ice should be treated as part of the cryocycle, not the hydrological cycle.  These glaciation and ice-sheet formation cycles are crucial to natural climate regulation.  We continue to learn about these natural cycles, but we already know enough to be deeply concerned about the implications of Arctic ice melt and glacier retreat.

Ice masses can absorb vast amounts of heat without melting and can return that heat to the environment.  Ice masses can lock up significant amounts of greenhouse gases.  They also hold masses of water at an elevation above sea-level for millennia. 

The cryosphere is a primary regulator of global climate and global sea levels.  It is one of our most precious global assets.

Geological cycles - volcanoes, earthquakes, plate tectonics, geomagnetic reversals, etc.

We urgently need to know more about our planet's geological activity.  We know from experience that mining can cause subsidence.  We know that extracting gas causes subsidence.  We know that just drilling in the wrong place can trigger a human disaster.  If we are to use geothermal energy we need to be able to predict with some certainty what the wider implications are.

Hydrological cycles - non biological - evaporation and precipitation, etc.

Under hydrological cycles I would include the cycles of natural catchments, aquifers etc.   I would also include saline intrusion into aquifers due to rising sea levels or post-glacial_rebound.

Meteorological cycles - atmospheric cycles

All cyclic atmospheric phenomena.  Major weather systems, atmospheric streams, layers and mixings, diurnal heating and cooling, etc.  This is a very widely studied area and is the primary component of climate models.

Nitrogen cycles

There are two major nitrogen cycles.  The one most commonly taught in schools is the plant-land-animal cycle - the nitrogen cycle of land.  The other major cycle, less widely known, is the marine_nitrogen_cycle.


Photochemical cycles - other than photosynthesis.

It is not widely known that many photochemical reactions occur other than photosynthesis in living things.  There are many natural and organic chemicals which are subject to reaction in the presence of sunlight.  The final by-product is commonly CO2.

In the past few years there has been an explosion of scientific interest
in the chemical reactions that happen in sunlit snow. Rather than simply
acting as the final resting place for pollutants that deposit from the
air, snow turns out be one of the most photoreactive regions on earth!
http://summit.ucdavis.edu/research.html


Thermodynamic cycles - thermal cycles and the links between all of the above cycles.

It is insufficient to model only the planet's diurnal, seasonal and annual thermal cycles.  Our environment as a whole exhibits a highly complex thermodynamic behavior.  Like a living thing, our planet may be viewed as if it is creating order at the expense of chaos.  As a living thing exhibits micro-behaviors and gives off heat, so our planet engages in macro-behaviors and radiates heat.

Since the dawn of civilization, we have dumped heat into our environment with no thought.  Today, we are beginning to understand the holistic thermodynamic behaviors of our planet.

Daily we dump ever more greenhouse gases into the atmosphere.  This slows down the radiation into space of heat from ground level.

Daily we dump more heat into the atmosphere at ground level than geothermal processes do.

Daily we dump hot CO2 and hot H2O into the lower atmosphere.  We argue about the possible effects of these greenhouse gases even while both sides neglect the thermal components of fuel consumption.

Using geothermal energy will serve to greatly accelerate the rate at which geothermal energy is dumped as low grade heat into the atmosphere at ground level.  It is immaterial if geothermal energy is CO2 free.  The laws of thermodynamics demand that every bit of geothermal energy captured by an energy scheme is injected into the lower atmosphere, mainly at ground level, as low grade heat.

Anthropovariant climate change

To say that something is anthropogenic is to imply that humans caused it.  This is a cause of some confusion and obtuseness: humans do not cause climate, say the critics.

Anthropovariance is any human-caused variation of a natural environmental cycle.
-----------------------------------

Discussion:

Is there any evidence of anthropovariance of any of the cycles mentioned above?

--------------------------------------
Credit:
Copyright free picture courtesy of
Harker Heights High School

Comments

Stellare
You make my head spin with all this cycles! :-)

I agree with you in that the Earth system is extremely complex, and our models are far from precise.

I too, think this singular focus on emissions as the major and only human contribution is wrong and contributes to take focus from better understanding.

An even simpler way of looking at this problem of whether humans are even capable of influencing the Earth system is to consider the rapid growth and shear number of humans on this planet now; in terms of the biomass it represent; in terms of various re-engineering of the planet, emissions being only one of many others like transforming the landscape to urban areas or cultural landscapes, to dams, infrastructure etc.

I would not dare to say that we know exactly how or how much, but based on that simple observation I'd say it is likely that humans do influence the Earth system.

Bente Lilja Bye is the author of Lilja - A bouquet of stories about the Earth

I think you summed it up nicely, Bente. And, I have to agree with all of your comments.

By our shear numbers and the industrial infrastructure in place to support such a large global population, I think it's safe to say that we are having an impact on the global environment. How much so and how exactly, I wouldn't dare to say either. No one really knows the answer to that question. We're still trying to figure the Earth's own natural rhythms for the last few billion years.

You say:
Daily we dump hot CO2 and hot H2O into the lower atmosphere. We argue about the possible effects of these greenhouse gases even while both sides neglect the thermal components of fuel consumption.

That is because the thermal components are utterly trivial. They do get mentioned from time to time, but only as a minor sideline in education to explain why they are so irrelevant.

Geothermal energy flow, for example, involves something from 40 to 50 TeraWatts of energy from within the planet coming to the surface. Human activities involve something like 16 TeraWatts.

That may sound a lot, but it is a drop in the bucket by comparison with the effects of anything that modulates the effects of the 175 PetaWatts coming from the Sun. It is common to measure energy effects per square meter, and a "forcing", in climate science, is anything that alters the energy budget of the planet. For example, to stop all energy use of all kinds by humans would save 16 TeraWatts, or about 0.03 W/m2.

The Earth's albedo is about 0.3, so Earth reflects a bit over 50 PetaWatts of the incoming sunlight. That's roughly 100 W/m2. So altering albedo by 0.03% would have a direct temperature effect comparable to removing all the thermal components of our energy use.

Or try a comparison with greenhouse effects. CO2 has a comparatively straightforward forcing, of 3.7 W/m2 per doubling. That is, you get a certain forcing for a certain percentage increase in CO2. To get 0.03 W/m2 would require 0.008 of a doubling, or increasing CO2 levels by a factor of 20.008, which is an increase of 0.56%.

But the current rate at which CO2 levels is increase is about 1.9% per year.

That is... one year's increase in CO2 has over 3 times more effect on Earth's thermal energy budget that stopping all direct thermal contributions of human energy dead. If you could some how capture all the waste heat from our energy use, and dispose of it somehow without letting it leak into the environment, you would have the same effect as delaying the continuously increasing CO2 forcing for just four months.

I've thrown a lot of numbers at you, but the short story is that climate scientists aren't stupid. The direct thermal component of human energy use is ignored because it is irrelevant. It is a drop in the bucket that would not even register with measurements of Earth's temperature or energy budget. It's not anywhere even in the ballpark.

Alas... the html tags did not work as advertised in my previous comment. In particular, the 20.008 should be 2 ^ 0.008. The relevant sentence should read:

To get 0.03 W/m^2 would require 0.008 of a doubling, or increasing CO2 levels by a factor of 2 to the power of 0.008, which is an increase of 0.56%.

I hope the above didn't come across as too snarky! It's a good thing, in my view, to try and get to a level of understanding of the details of things like this. There's a lot more in your blog article here as well, which some of which can be covered quite well and some of which are significant sources of uncertainty. Sorting that out is worthwhile, but it takes a bit of work to get to grips with the relevant science.

I am about to launch a new project for helping people get to grips with the science of climate, so as better to follow the various disputes that go on. Keep an eye out for it!

logicman
I hope the above didn't come across as too snarky!

Not at all!  Anything that stimulates scientific debate is welcomed and encouraged.  Indeed, compared with the ad hominem comments I sometimes get on climate, your comment is a positive accolade!


Whilst I agree with you that human thermal input would be trivial if averaged out across the planet, the simple fact is that it is not averaged out. Firstly, it is localised in space, thus we have the heat island effect.  Not only can you measure that effect, but I can tell you from personal experience that in cycling between city and country over a few miles one can feel the effect. 

Secondly, insolation follows day-night cycles which vary with latitude and season.  Human heat output tends to be fairly invariant.  Just to give one example, London's temperature both night and day can be about 2oC above surrounding countryside.  Those tenths of Watts add up to a real cumulative impact.


If we were not putting greenhouse gases into the atmosphere, then our heat outputs could be ignored.  But increasing the planet's heat input whilst simultaneously increasing its 'insulation' is a bad idea.  When you look at localised heat gradients coupled with greenhouse gases, you get the impression that sooner or later the safety valve is going to pop.
I am about to launch a new project for helping people get to grips with
the science of climate, so as better to follow the various disputes
that go on.

Why not blog here?  I don't mind a bit of competition to my climate articles.  Let's work together and explain, from different perspectives, how we must learn the lessons of the past or reach an irrecoverable tipping point.

Thanks for your stimulating inputs, Sylas.

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