Since the so-called “Climate-gate scandal” that erupted just before the Copenhagen conference last year, journalists and those denying human causes for climate change have felt quite good about themselves – as if the “Climate-gate scandal” had vindicated their position. If you don’t believe that there is a link between human activity and climate change, then before you read further, just ask yourself this: “what was the essence of the climate-gate scandal?” I have found that most people don’t know. (The answer, by the way, has very little to do with actual data on climate change).

But the issue underlying “Climate-gate” happened in 2007. Science hasn’t stopped since then. Now a new series of studies has been released, showing even more evidence of the role of human activity in global warming and climate change. The New Scientist has just released a nice list of these bits of research. You can see them here, or an extract below.

Climate change deniers are going to wake up one day and be very embarrassed. They’re like those who denied links between cancer and cigarette smoking. And they’re similraly being well manipulated by big corporate money (why did the Climate-gate scandal only come out weeks before the Copenhagen conference?).

The evidence continues to mount… We must change the way we live on this planet.

Which climate changes can be blamed on humans?

by Michael Marshall, reporter

The conclusions of the last IPCC report were unequivocal: it said, with 90% certainty, that greenhouse gases released by human activity were warming the planet. That was then and this is now, and since the IPCC’s report came out in 2007 climate science has come under some criticism – rather a lot of it in fact. So it’s no surprise that when new papers confirm the IPCC’s conclusions, climate scientists are not shy about advertising them.

The latest example of such a paper, in press in WIREs Climate Change, reviews a number of studies that have been done since 2007. It finds that there are definite human influences on a host of aspects of the climate, all of them driven by the rising temperatures.

All the papers that Peter Stott of the UK Met Office and colleagues reviewed attempted to find a human “fingerprint” on the climate. They focus on data that has been collected over the last century. They calculate the relative influence that different factors – including natural variations like changes in the Earth’s orbit, and human-made influences like carbon dioxide emissions – have on the changing climate.

According to Stott’s overview of published research papers, there is now a confirmed human fingerprint (links go to the original papers) on:

• The rise in global surface air temperature;
• The rise in surface air temperature over every continent, including Antarctica;
• The rise in atmospheric humidity (caused by the higher air temperatures);
• The rise in precipitation (rain, snow, etc) around the world, as a result of the higher humidities;
• Shifts in precipitation: dry tropical regions are getting drier while wet regions closer to the poles are getting wetter;
• The huge losses of Arctic summer sea ice;
• The rise in surface ocean temperature;
• Increasing salinity in the Atlantic Ocean.

The researchers say that a fingerprint study of this kind has not yet been performed for sea level rise, and that we still cannot be sure whether humans have had an effect on the number, or intensity, of hurricanes.

It’s hard to take the promotion that Stott’s review received – it was press released and presented at a press conference – as anything other than a response to the unremitting onslaught of climategate-related accusations being hurled at climate scientists at the moment.

Will it make much of a difference to the controversy? Hard to say. But it’s worth pointing out that very little of the fallout from climategate has had to do with the evidence for human-driven climate change. Rightly or wrongly, journalists seem more interested in flaws in climatologists’s characters than the strength of their data.

Source: New Scientist, 5 March 2010