Climate change: is the science really settled?
 

Climate change: is the science really settled? - Today, the IPCC releases its latest report on the science of climate change. At least, that's what the headlines will say. In fact, this is the first stage of a staggered publication of the organisation's Fourth Assessment Report (FAR), which supersedes the third report, published in 2001. But this first tranche is not, as might be expected, the full weighty document, in which all available evidence is evaluated and carefully summarised. Instead this is the so-called Summary for Policymakers (SPM), a short (only 14 pages in draft) summary of the key points. This is the text which nearly everyone will be quoting from over the coming months and years.

Not only is it an unusual step to publish the summary of a document which has not yet been finalised and released into the public domain, but the summary itself is not necessarily quite what it seems. Rather than simply being an attempt to summarise the main points from the much longer report, the SPM is a political document, agreed line by line by the governments of the countries which are members of the IPCC. Only the release of the complete chapter will enable those with sufficient staying power and understanding of the science to compare this with today's document, but the experience from the Third Assessment report was that there were clear messages coming from the SPM which did not necessarily represent a balanced view of the science. In other words, there was spin.

Interestingly, after a ramping up of concerns as the previous three assessment reports were published, the TAR tones down some of the more extreme projections which have been headlined in the past. The report seems set to say that, if carbon dioxide levels reach (and are constrained to) 550ppm (effectively a doubling of the reported pre-industrial average of 280ppm) the ultimate average temperature rise is likely to be 2-4.5 degrees C, which is a narrower range with a reduced upper limit. By the last decade of the century, projected temperature rise is in the range 1.7-4 degrees C compared with the 1980s, for a range of emissions scenarios. Sea level rise is projected as 28 to 43 centimetres over the century, with two-thirds of that being due to thermal expansion. These figures are lower than previously suggested.

However, the headline news will not be these projections or the fact that they have been moderated, but the fact that the IPCC now says that anthropogenic greenhouse gas emissions are 'very likely' to be the primary driver of recent climate change. 'Very likely' is defined as between 90 and 95% certain. But this 'certainty', which will be used constantly to discredit any dissenters, is based on the unproven assumption that the climate scientists and modellers have such a good understanding of natural climate processes that additional greenhouse gas emissions are the only possible cause of rising temperatures in recent years.

At present, we regard the link as a plausible but unproven hypothesis. While modellers claim to be able to reproduce the very variable trends of the twentieth century (by including allowances for aerosols, for example), this smacks of tinkering to get the right answer rather than a way of improving the realism and reliability of the models. Only time will tell whether the projections are anywhere near right but, in the meantime, we should remember that there has been no upward temperature trend in the last eight years.

We are quite prepared to have our scepticism proved wrong if new and convincing evidence emerges. We could be wrong. It will be progress indeed when the IPCC and scientific establishment says the same.

We are pleased to say that the Frazer Institute, a Canadian think tank, will be launching its own Independent Summary for Policymakers in London on 5th February. We hope that this will help to foster debate. (Scientific Allaince)



http://www.junkscience.com/

No, it's not settled.

First of all, no one single scientist can tell you that the outcome of Global Warming, assuming that it is happening, is all bad, half bad, or not bad at all.

Further, since the earth has been significantly warmer many times in the past; not a single scientist can tell you with certainty that Global Warming is even slightly related to human activities.

I cannot believe this is even a subject for debate anymore.

Shall we get to the bottom of this 'Is the earth round or flat?' controversy as well?

Ridicule doesn't cut it in this debate, and in science, debate is a part of the process.

For example, there's the discovery of significant mathmatical errors in the "Hockey Stick Projection", which totally destroyed that theory. The Hockey Stick Projection had been taken as gospel for some time.

Not exactly from an unbiased source.

And BTW its' the Fraser Institute not Frazer. They are a conservative think tank with their own agenda. http://www.fraserinstitute.ca/

Global Warming is just a theory, haven't you heard?

Global Warming has occured on the earth many times in the past, Global Warming as a result of human activity is a wildly unproven theory.

It is, however, the socialists wet dream.

Damn, I kind of agree with you, Pat.

Have any of you ever seen six BILLION of anything in your entire lives? That's how many people live on the planet right now. Think of how much impact you have on the world during the course of your life - how much you consume, how much waste you produce, how much you pollute, etc. Now multiply that by ten. Now multiply THAT by ten. Now multiply that by ten again. Now multiply that by a THOUSAND. Now multiply THAT by ANOTHER thousand. That's the impact of 1/6 of the people on earth - and that's just the ones that are here right now. Yes, we have an impact. It's a big problem and we do need to do something about it.

The root of almost all our problems is simple overpopulation.

+1

The current-day extremist environmental movement is as much about avoiding damage to our land, sea and water, as the feminist movement is about women or the civil rights movement is about minorities.

The environmentalists aim to cripple capitalism and extort money from industrialized nations, in particular, the United States.

When you compare all human waste mentioned, it pales in comparison with that of the insect world.

The earth isn't close to being overpopulated.

That's is correct.

Global warming and CO2 levels are closely related, this is a fact. CO2 levels are higher than they have ever been, this is another fact. Human activity produces CO2, that is undeniable. Now, you may refuse to add 1+1+1=3 and keep your collective heads in the sand. Just don`t come crying to me when our Porscha is under water.

Aurel

Global warming has occured many times in the past, it's not related to CO2 in the atmosphere at all.

Pat, the correlation between CO2 levels and earth temperature is a proven, scientific, solid fact, demonstrated by ice core studies several times. The fact that you deny it does not surprise me, but if you wish to educate yourself a little bit on how these measurements are done, read on. Then we can discuss.

http://www.sciencemag.org/cgi/content/short/310/5752/1313/

Aurel

So what caused each of the umpteen previous ice ages to end? Uh, global warming.

I was watching the news a few weeks ago when they said this was the 8th warmest January 3rd on record. So that means there have been 7 previous ones that were warmer and that was only in the last 100 yrs. or so since we've had records.

It's the height of human arrogance and self-importance to think we control global temps. and that a 1-2 deg. rise in 100 yrs. is something we need to worry about. If the time from the big bang to the present were measured by a football field, the amount of time humans have been on the Earth would be about as wide as a human hair on the goal line.

We have polluted oceans to the extent that fish is contaminated with heavy metals and is no longer safe to consume. We have clear-cut most of the Earth's old growth forests...Put a huge hole in the ozone layer. Now Ice caps are melting and glaciers are receding. How can you not realize the impact that humans have on the health and natural balance of the Earth!

Aurel, how do you explain the periods of global warming while CO2 levels were dropping between ice ages that those very same ice cores indicate?

You are confusing very local man-made problems with issues on a much larger scale--that it is still unproven that humans can even influence.