"Each of the last three decades has been much warmer than the decade before. At the time, the 1980s was the hottest decade on record. In the 1990s, every year was warmer than the average of the previous decade. The 2000s were warmer still.”
                                                                                         NOAA, "State of the climate, 2009"

"Sixteen of 225 nations on Earth have set extreme highest temperature in history records this year, the most of any year. The year 2007 is in second place, with fifteen such records."

                                                                              Dr Jeff Masters, Weather Underground, August 2010

"Don't the climate alarmists know that proxies are only any good at proving that the MWP was a really really warm global phenomenon when the world warmed up for no reason at all which PROVES that the world can warm up for no reason at all at any time and it's nothing to do with us. Except that the world isn't even warming up. And if it is warming up it's for no reason at all."

Despite each and every twist and turn in the circular arguments offered by the politicised opposition to climate science, events are unfolding pretty much as the science has indicated that they would. Enhanced monsoon rainfalls in Pakistan have affected as many as 12 million people, causing death, homelessness, destruction of property and infrastructure in the resultant floods. Tremendous flood events have also affected China and the American Midwest. Elsewhere, prolonged drought and record-breaking high temperatures have been experienced - notably over a large part of Russia where wildfires have added to the chaos. The Russian grain harvest has been severely affected as a consequence, which in turn will reduce the amount available for export with the attendant threat of increased food prices. Ironically, some parts of South America have witnessed unusually cold winter conditions. Overall, things are not looking so good in many places.

above: TERRA satellite image of an area SE of Moscow, showing the smoke from wildfires, 02/08/2010.

I've never been a fan of the term "Climate Change". Looking at what is currently going on, I find "Climate Destabilisation" more apt. I'll explain why.

Although there have always been severe weather outbreaks around the planet, in the past 5000 years or so, during which human civilisation developed on a large scale, the frequency of extreme conditions has remained relatively steady. That relatively stable climate has been a major factor in our societal development: it has, most of the time, permitted us to grow food and expect to be able to harvest it, to develop infrastructure on the surface of the planet and expect to be able to go on using it. As a consequence, we are very tied-down to the ground around us: unlike nomadic peoples, we cannot just simply up and move on if conditions necessary for population support deteriorate.

Any increase in the frequency of extreme conditions has the potential to undermine a lot of what we have achieved as our civilisations developed over these past few thousand years. That's why I term the risk we are taking as "Climate Destabilisation".

WHAT CAN BE LEARNED FROM THE PAST?

To get this framed into some kind of perspective we need to look back at the climate of the more distant past, which, although relatively stable in terms of the history of our civilisation, has exhibited major changes over a much longer (geological) timescale. Earth's geological history records periods of much warmer conditions than those of today (hothouse) and also relatively short (on the scale of a few million years) periods dominated by fluctuating cold (glacial) and mild (interglacial) conditions (icehouse). We live within an interglacial today. Transitions from interglacial to glacial and back typically take thousands of years to occur: for example, the last glacial maximum was about 18,000 years ago but the transition into the familiar climate of the modern age - the Holocene - was only complete 10,000 years ago.

Large-scale climate changes of this type are caused by a number of factors  - "forcing agents" - working together. The climate record featured below (reference 1 at the end of this page) is from an Antarctica ice-core from which data have been obtained going back more than 400,000 years. It shows a regular series of spikes along the blue line (temperature) that mark the interglacials and dips that mark glaciations. It is important to point out that any one of these major fluctuations either way, if it happened now, would disrupt human civilisation on an unimagineable scale.

The green line - carbon dioxide levels - shows a strong relationship with temperature: so much is clear. However, it is not exact. The carbon dioxide levels at the start of each warming phase lag behind the temperature a little - a few hundred years. This feature has been gleefully seized-upon by the political opposition who have incorrectly used it to opine that it means carbon dioxide cannot be a driver of temperature. I'll explain why they are wrong.

Analogy is often a useful way of illustrating scientific arguments and it is so in this case. So - if you take out a bank-loan of say $1000, you are $1000 in debt straight away - OK? But after the first month, the statement arrives and you find that you owe more than $1000 because of the interest that has been added on. The debt came first, but then the interest made it bigger. The amount of increase due to interest will vary according to interest rates or whether you went to the bank or a loan-shark. But just because the debt came first, it doesn't mean that the interest won't add to it!

Think of the carbon dioxide as the interest. The initial trigger of the warming is the equivalent of you going to get the loan. In glacial-interglacial cycles, the triggers are the Milankovitch Forcings - the various orbital variations that happen on a regular basis every few tens of thousands of years and that affect the amount of solar radiation received by the Earth's surface by a little more or a little less. In the transition to an interglacial, Milankovitch Forcings cause the first few hundred years of warming but after that, feedback mechanisms for large-scale carbon dioxide release caused by increased temperatures come into play. These include permafrost melt and release from the oceans - and it is then that the "interest" kicks in as carbon dioxide, due to its heat-trapping properties, acts as a warming amplifier.

The graph above shows carbon dioxide levels varying between about 180 (glacials) and 290 ppm (interglacials). Current levels are around 390ppm, with the extra having been added by fossil fuel burning since the Industrial Revolution (in geological terms, strictly a "one-off" event) and they are rising year-on-year, so they are way above any point over the past few glacial-interglacial cycles.

above: the Kremlin through the smog - screengrab from a video - August 6th 2010

LATEST POLITICAL PERSPECTIVES

So, how are the politics shaping up these days?

At first glance, nothing much seems to have changed (see reference 2 at the end of this page). The same old arguments are being trotted out by the same people - it is virtually copy-and-paste, copy-and-paste. However, I and others have recently noticed one interesting thing: the pretty much simultaneous iteration, or in some cases reiteration, of the stance of some of the leading members of the political opposition. Here's an example (reference 3 at the bottom of the page - with the important bit highlighted):

"I am delighted that this simple and clear but authoritative statement of the reality of the "greenhouse effect" has been posted here. Too many inaccurate statements to the effect that there is no greenhouse effect have been published recently, and they do not deserve to be given any credence. The true debate in the scientific community is not about whether there is a greenhouse effect (there is), nor about whether additional atmospheric CO2 causes warming (it does), nor about whether CO2 concentration is rising (it is), nor about whether we are the cause (we are), but about how fast CO2 concentration will rise (for a decade it has been rising at a merely-linear 2 ppmv/year, against the IPCC’s projection of an exponential increase at today’s emission rates), how much warming a given increase in CO2 concentration will be expected to cause (around a third of what the IPCC projects), whether attempting to mitigate future "global warming" will make any real difference to the climate (it won’t: remember Canute), whether the cost of forestalling each degree of "global warming" will be disproportionate to the climatic benefit (it will), and whether focused adaptation to any change in the climate, where and if necessary, will be orders of magnitude cheaper than trying to prevent that change from occurring in the first place (yes)."

This may well be the first and last time that I quote Monckton of Brenchley on here! However, this post, on the political opposition website Watts Up With That, and the guest post by Ben Herman and Roger Pielke Snr it refers to, and a similar piece by Roy Spencer on his own site at broadly the same time, set out the stance that the greenhouse effect is real, additional carbon dioxide causes warming, it is rising and we are the cause. Where these predominantly political writers now seem to differ with most climate scientists is with respect to how much warming is likely to occur and whether it is worth doing anything about it. Thus, it appears, the political debate is being reframed.

That is in strong contrast to many who vociferously insist that the whole thing all the way from the "greenhouse effect" upwards is a "scam" or "hoax" and it was interesting to observe the responses in public comments, some of which were openly hostile to their onetime heroes. Yet this is a common feature. Read through any online debate on climate science and the variety of "alternative" theories to explain how the climate works is as diverse as the pebbles on a beach. The only thing they have in common is that carbon dioxide cannot possibly be involved!

Scepticism is an important quality for any good scientist. To seek the truth, each set of observations, each hypothesis, each conclusion and each paper requires questioning and scrutiny - as indeed goes on in all the scientific disciplines. You don't get such a thing as "proof" in science: what you have in the strongest theories is an overwhelming weight of scrutinised evidence in their favour.

Scepticism involves that process of questioning, scrutiny and weighing-up. However, what one sees on the blogosphere is completely different in many cases. Here, firstly carbon dioxide is unconditionally rejected from the equation and secondly, alternative theories published on other blogs by leading Opposition members are often unquestioningly accepted - indeed, welcomed with open arms. To call the people who are doing this "sceptics" is a completely incorrect use of the word. They are simply rejecting something that they find politically indigestible and clutching at any straws that appear to support their worldview. That is why some refer to them as "deniers", though, having looked into the situation in some detail in recent years, I now prefer "political opposition", because, although in some cases a state of denial (a perfectly common human reaction to a perceived threat) is evident, the nature of the online debate is primarily political - there is as much focus on the people, and often much more, than there is on the hard science.

Science and politics also work on different timelines with politics tending to be focussed on the short-term. We geologists play about with multimillion-year timescales and climate predictions cover decades and centuries - quite different timescales to the year-by-year economic fluctuations that politicians wrestle over. I am sure that this is also a factor in the political opposition to climate science.

A classic example of the timescale effect occurred last winter - at least in the areas where it was unusually cold, such as the UK. The opposition loves to point out that a single flood, storm or heatwave is just "weather" and "proves" nothing about climate. But if I had a pound for every time, last winter, that I read on a snowy morning, on some message-board or other, "so much for global warming!" I'd now be extremely wealthy! But, on the other hand, the weather disasters occurring in Russia, China, Pakistan and elsewhere are consistent with climate predictions that indicate a greater frequency AND severity of such things. By the way - the predictions don't eliminate cold winters from the picture for the time being, either. But to finish with, as the NOAA's Deke Arndt recently put it:

"Climate trains the boxer but weather throws the punches".

References

1. Petit J.R., Jouzel J., Raynaud D., Barkov N.I., Barnola J.M., Basile I., Bender M., Chappellaz J., Davis J., Delaygue G., Delmotte M., Kotlyakov V.M., Legrand M., Lipenkov V., Lorius C., Pépin L., Ritz C., Saltzman E., Stievenard M. (1999). "Climate and Atmospheric History of the Past 420,000 years from the Vostok Ice Core, Antarctica". Nature 399: 429-436.