photo credit : James Hansen, NASA GISS


Climate Smash & Climate Squish
by Jo Abbess
25th April 2008

* Energy Balance
* Fast and Slow Responses to Global Warming
* Global Warming Time Lag
* The Saving Polar Ice Caps
* Self-Reinforcing Effects
* It's Happened Before But For Different Reasons
* Better Back Down Fast

OLD CULTURE : NEW EXPRESSION

In the last few minutes I have heard a handbell being rung outside in the street. A large white open-backed van has thrumbled and purred past, chock-full of large metal equipment, wiring and furniture, and the passenger was shaking his hand up and down to clang and clang.

This being East London, some people reading this will know what this means. No, it's not the Medieval call of the priests with handcarts calling to take away the bodies of the victims of Yersinia Pestis.

It's not "Bring out your dead !", it's "Bring out your dead white goods !" as this is the Big Trash service of the Local Authority.

This activity used to be undertaken privately by people known as rag-and-bone-men, but it's been brought bang-up-to-date as a modern expression of mandatory public service recycling.

ROCKS & RULES

In the last weeks, the scholarly 18th and 19th Century studies into Geology and the 20th Century enquiries into Geophysics have been brought sharply into relief as the European Geosciences Union in Vienna acted as a platform for the unveiling of startling new data on Global Warming.

It's suddenly fashionable once more to be interested in rocks and things that died many years ago. Astonishing facts, figures and theoretical projections have been presented, and although journalists have not always understood the implications of what is being said, they have understood the general tone.

The stability of that part of the Earth system we call home is highly at risk from Global Warming and Climate Change, and the Geographers and related professionals are yanking the cat out of the bag (or the rabbit out of the hat, if you prefer) for all to see. It's high time that people started to pay serious attention.

ENTIRELY NEW THINKING

I've been reflecting over the last month upon several research papers, principally that from James Hansen et alia :-

http://www.columbia.edu/~jeh1/2008/TargetCO2_20080407.pdf

I wanted to try and get a feeling for all the processes and effects they talk about, as I wanted to be able to describe them properly, without using numbers or graphs.

I want to pick out what here what I consider to be the most important concepts to hold on to, descriptions that I hope will have a pictorial effect in your minds. If you can hold onto these ideas, you may be able to make sense of what unfolds, and help you to take appropriate action.

OUT OF ENERGY BALANCE

What Hansen and his colleagues have tried to demonstate is that any change in Carbon Dioxide in the Atmosphere causes a Global Warming or Global Cooling effect.

This they did by considering different geological time periods, looking at all the available proxy and real data from the physical records.

One period in pre-history shows that at the time that the Antarctic Ice Sheet formed, the amount of Carbon Dioxide in the Atmosphere was dropping sharply, cooling the Earth.

The picture I have in my mind is this : imagine a long line of coaches moving at the same speed along an inter-city high-speed road (a motorway, an autoroute...) Imagine that one coach brakes sharply. All the other coaches behind it will crash into it.

The thing is, it doesn't matter which speed they start out at. If they are travelling fast or slow, any change in speed of one of them will cause bunching.

This is the same with the warming effect of Carbon Dioxide. At approximately 34 million years ago, the level of Carbon Dioxide in the Atmosphere plummeted, and massive glaciation took place as a result of the Global Cooling that ensued.

The count of Carbon Dioxide in the Atmosphere was higher than it is today, but reducing it caused Global Cooling.

Today, Carbon Dioxide levels are rising sharply, so we can expect Global Warming.

Because Carbon Dioxide has a warming effct, changes in the levels of Carbon Dioxide put the Earth system out of Energy balance, and it must adjust to the new conditions.

CLIMATE SMASH & CLIMATE SQUISH

Imagine if you will a lump of dough, made with flour, water, sugar and yeast, that has been left to prove and aerate and expand for a little while. Picture tearing a piece of the dough and putting it on a floured table, and then punching down on it with a clenched fist. The dough will collapse instantly in the shape of your fist.

But what happens if you continue to keep pressing down on the dough ? Over the period of a minute or so, it will start to squelch out at the edges around your fist, bulbing and bulging out of the pressure zone.

This is a representation of what James Hansen refers to as "fast" and "slow" feedback Climate Sensitivity.

In other words, it can be understood that there is a relatively rapid response of the Earth system to Global Warming, but it is clear from the data from ancient history that there are also slower processes that occur during a Global Warming or Global Cooling episode, over a longer timescale.

Hansens' team take the data from drilled ice cores and other sources, and show that the Fast Feedback is somewhere in the region of 3 degrees Celsius (roughly 5.4 degrees Fahrenheit), on average, globally.

They use the same series of data to deduce that Slow Feedbacks can ammount to somewhere in the region of 6 degrees Celsius (roughly 10.8 degrees Fahrenheit).

The concern is that although Life on Earth might be able to survive the Fast Feedback, it might not be able to survive Slow Feedback.

GLOBAL CLIMATE TIME LAG

There are many factors at work in Global Warming, one of the major ones being that the Earth system does not warm uniformly.

Ocean and Atmosphere warm at different rates and with different trends and cycles. Various elements of the Earth system have both Global Warming and Global Cooling impacts, and it takes time for these effects to resolve one way or another.

One thing is clear : the near-surface land temperatures have not caught up with the implied amount of warming calculated from the known Carbon Dioxide Emissions.

This means there is a time lag between known "radiative forcing" and the full warming effect.

Imagine this : drop an icecube into a cup of hot water. The icecube does not melt in an instant. It takes time to equilibrate. This is the time lag of Global Warming.

We have experienced a rise of 0.7 or 0.8 degrees Celsius since the Industrial Revolution, but there is another 1.4 degrees Celsius "in the pipeline" coming to us from the Emissions we have already made.

THE SAVING GRACES : HOW THE POLAR ICE CAPS ARE PROTECTING US

What comes across clearly from the Hansen paper is that were it not for the polar ice caps, the total warming feedback would be much faster than it is.

The polar ice caps are in fact protecting us from catastrophic Climate Change at the present time.

However, the most recent news is that massive changes are afoot in the Arctic, which could mean and ice-free northern Arctic Ocean within 10 to 20 years.

As the Arctic sea ice melts away, so will one of our defences against dangerous warming.

SELF-REINFORCING EFFECTS

Carbon Dioxide Emissions cause Global Warming which causes Carbon Dioxide Emissions and other Greenhouse Gas Emissions.

There are other mutually self-reinforcing effects that are becoming possible.

The news in the last 48 hours is about how global airborne Methane levels have started to rise again, after stabilising for several years. These increases are not due to increases in farming livestock, so they must be due to other effects. The most likely ones include the melting of the permafrost and the warming of underwater shallow continental shelves, both of which could presage increased Methane Emissions.

IT'S HAPPENED BEFORE, BUT FOR DIFFERENT REASONS

Yes, Global Warming has happened before in Earth history, but it is clear from the geophysical and biophysical record that those phases were caused by different reasons than today.

The tectonic movement of the India plate which resulted in it joining with Asia, most likely caused a massive outgassing of Carbon Dioxide and other Greenhouse Gases, as indicated by the geological records.

The warming effects were fast and furious, but eventually the Earth recovered its balance.

BETTER BACK DOWN FAST

We need to reduce Carbon Dioxide Emissions into the Atmosphere, caused by the burning of Fossil Fuels and deforestation, peat-burning and other man-made change.

The Hansen paper makes the point that if we reduce emissions rapidly, we may be able to avoid the full force of the slow feedback warming, as the "Climate Inertia" or time lag allows us time to get cooling again before the slow feedbacks melt all of the ice on Earth.

The picture is this : I put a teaspoon into a very hot cup of coffee. If I'm quick, I can stir the coffee and take the spoon out of the cup before the heat transport through the metal of the spoon causes me to burn my fingers !


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