climate change – Defrosting the Freezer

Arctic sea ice over one year

As 2014 draws to a close, what were the key features of the Arctic climate this year? Today let’s look at the sea ice coverage. The US National Snow and Ice Data Centre has a monthly running commentary on ice cover on their website, and in general 2014 has been “extremely ordinary”, by which they mean that sea ice grew and shrank at roughly the rates of the last few years. Ice cover was not as low as 2012, the record-breaking year for sea ice retreat, instead it was pretty average for recent times. Remember that this is still way down on the long-term average.

Monthly Arctic sea ice cover for the last few years (NSIDC)

Using their monthly data, here is an animation of the sea ice changes over the last 12 months. It’s a reminder of just how dynamic the Arctic is. Sea ice cover is important for a number of reasons. First of all, the white colour reflects sunlight that shines onto the ice surface during the summer. Reflecting sunlight back into space means that it does not stay around to warm our planet, so having a decent covering of ice helps to regulate temperatures. As the summer sea ice cover has decreased in recent years, the amount of sunlight reflected back into space has decreased, meaning that there is a positive temperature feedback at work here.

animsm — Arctic sea ice cover over the last year

Sea ice cover is also important for the Arctic Ocean’s biological cycle. Many plankton require sunlight for photosynthesis, so the retreat of sea ice during the spring and summer causes a bloom in biological productivity in the surface ocean which feeds down the food chain, supporting large numbers of fish and whales. As organic geochemists, we can see this plankton bloom by looking in the ocean sediments biomarkers. There are specific chemicals that are produced by marine organisms that can be used to track the productivity, and it seems that there is a direct link between the ice-free areas and the highest amount of biological activity.

Manchester Museum – Siberia Exhibition

Starting this Saturday 4th October, and lasting until 1st March, the Manchester Museum will be holding a special exhibition on Siberia. This will contain a collection of special items from British and Russian museums, including a mummified baby mammoth and a brown bear, along with displays on the culture and natural history of the region, taking visitors beyond the stereotypical view of Siberia as an icy wasteland. Along with colleagues in Manchester, Newcastle and London, I have made a display board and video about Siberian climate change, which will be showing throughout the exhibition. More to follow once the exhibition opens…

US Government review of climate change

This week the US government released their own review of the climate, including the current state of play and predictions for the future. They conclude that climate change is happening now, affecting lives today, and not just something to worry about 20+ years in the future.

Modelled temperatures with and without human CO2 emissions

The report website is very comprehensive and well-written, and I’m not going to reproduce it here. The section on Alaska, complete with interactive photos and charts, is relevant to permafrost research across the whole northern hemisphere.

State of the climate – a 2013 snapshot

NASA measurements — 2013 Temperature Anomaly

In January, NASA and NOAA (the US National Oceanic and Atmospheric Administration) released a joint statement on the temperature and climate patterns seen in 2013. Their short presentation (PDF) gives a summary of last year’s data in relation to long-term trends and averages. Of particular note for Arctic scientists is the relatively cool high-latitude temperatures in mid-summer. These lead to less summer sea-ice melting compared to the previous year’s record-breaking minimum, causing nonsensical headlines from the usual suspects that the world was cooling down. As slides 2,3 and 8 show, 2013 was one of the warmest years on record, while slide 11 shows that Arctic sea ice was still far below average last year.

Polar ice cover graphs — Polar ice cover through time

Public perceptions

A new report from Yale has found that “belief” in climate change among the American public is decreasing, and that now less than half of people believe that climate change is man-made.

So why is this? My personal guess is that we’ve all got a little bit of David Cameron inside us, and when things got tough we decided to “cut the green crap”. Shrinking fincances have led to a more selfish outlook, we just can’t justify spending more on sustainable energy when there are other, more basic, needs to consider. Couple this with a natural desire to believe that whatever bad things happen are not our personal fault, and an increasingly vocal climate skeptic lobby, and it’s understandable that people would want to switch sides.

But wait, burying our heads in the sand is not the answer. Things have changed recently, measurements have been taken and trends have been spotted that, with the right spin on them, would appear to play right into the hands of the global warming deniers, yet the reality is that we should be as concerned as ever about the future of our planet. Recently I have spoken to several well-educated, some extremely well-educated, people who, despite all the coverage are unconvinced that we, you me and 7 billion other human beings, are responsible for the changing climate, or even that it is changing at all. This seems to be a new thing, a few years ago they might have been on the other side of the debate. Has climate skepticism become fashionable?

I’m not about to start presenting all the data and rebuking every argument about climate change, the volume of data is too large and there are so many points to argue about that I don’t have the time. However, lots of other people do have the time:

The latest IPCC report is probably a good start if you want the “official” summary:

http://www.climatechange2013.org/images/uploads/WGI_AR5_SPM_brochure.pdf

A more targeted and less hardcore site goes through the climate skeptic arguments one by one:

http://www.skepticalscience.com/

And now for my two-pence worth. It’s mostly an appeal for common sense, from both sides of the argument. Journalists are always keen to get a good story, and people with opinions are always keen to emphasise evidence that they are right. However, our planet is a complex system and a single piece of evidence does not sway things. 2012 was a record-breaking year for ice cap retreat in the Arctic, the summer ice coverage was the lowest ever. This led to a lot of reporting which, justifiably, picked up on this and suggested that it might be a bad thing. But did they go too far? Was one data point enough to justify widespread panic? Probably not, but it was something to bear in mind and consider along with all the other available evidence. Subsequently, since we are not yet in a run-away global warming apocalypse, when 2013 failed to break the record again and was merely in line with other data from the 2000s, the journalists on the other side of the argument got to crow that the world was cooling down again. Now they’re almost certainly wrong in every degree – a quick look at longer-term trends would show that 2013 was still far lower than the average and that ice thickness is reducing quickly – but both scientists and science journalists must beware of crying wolf based on a single year’s data.

Getting people worried about climate change was a good thing, but doomsday prophesies about massive immediate changes that have not been borne out will only lead to disbelief. Just like the size of the ice cap, public belief in global warming is probably due to a number of nebulous factors and might fluctuate from year to year and we as a scientific community must be sensible about the way in which our concern is projected in the media, concentrating on boring but incontrovertible long-term trends rather than sexy but one-off events. As ever, climate != weather.