Although the temperatures in the Arctic are climbing rapidly, this can be stopped by ending pollution from soot and unburnt diesel. This is important if we still want to hold temperature increases to 1.5°C.
Arctic temperatures have been rising since 1994, yet have only recently been the focus of academic attention and, as a result, to come to the attention of climate commentators. This is a pity because addressing the problem of pollution from soot and unburnt diesel would have solved much of the angst felt on both sides of the climate debate and made the debate much more civil.
Only recently, a climate change leader, Sir David King, made the entirely unsupportable claim that we should be get back to 350 ppm of CO2 (we are currently at 420 ppm). Who will pay for this? What benefits does it offer? While this idea has been around for about 10 years, it refuses to get any traction from governments. It is not surprising, for there is no evidence that CO2 at 350 ppm is better than 420 ppm. Even the hot summer in Europe, north America and China cannot be directly attributed to current levels of GHGs. Metrologists are currently attributing this to a severe El Nino on top of climate change impacts, but this is a guess.
Perhaps the 350 ppm target reflects the fact that this was below the level of CO2 around 1995. Certainly this can be considered the last date before passing the trigger point of arctic temperatures. Yet, the fact that the arctic passed this point in that year was not only due to CO2 and other GHG emissions. It was due to fact that soot and unburnt diesel emissions (i.e. black carbon) had been allowed to increase in the arctic since the 1880 at least. If the effect of greenhouse gases in the arctic atmosphere followed the global trend, then only about 70% of the temperature increase from 1880 to 1994 (1.4°C = 1.5°C since industrialisation) can be attributed to GHGs. To what can the remaining 30% of the temperature increase be attributed? Surely to black carbon.
The problem of such pollution is a problem even to a casual observer. As Fiona Harvey reported, “The vast expanse of ice and snow covering the Arctic may look startlingly white from a distance, but on closer examination the glaciers and snow cover are patched by dark streaks of inky black and dusty grey and brown. Some are small and self-contained; others are miles long. All are the mark of man.”
Why is black carbon a problem? This is because it reduces the reflectivity of ice and snow. Instead of the ice and snow reflecting up to 90% of the sun light back to atmosphere, more of it is absorbed into the ice cover, causing the heat to be retained within the earth surface. Technically, this is reduction of the earth albedo. This is not a change to the GHG-caused warming. It is a different part of the climate equation, for which there are three parts: albedo, solar radiation and GHG gases.
A large part of the failure of climate scientists to consider the problem of black carbon has been an excessive focus on GHGs, and the assumption that changes to albedo only arise from changes to GHGs. This excessive focus, one could call it an obsession, continues today. Why is this? Can anyone excuse this obsession?
Albedo changes in the arctic
Changes in solar radiation has had little effect on global average temperatures over the last 140 years: it has been mostly due to GHGs. More recently, the fall in albedo has had a dramatic impact on arctic temperatures. Now that the Arctic temperature is increasing, changes in albedo have become quite important and are to key to bring arctic temperatures under control. This means that soot and unburned diesel have to be managed down to zero.
Here is the current state of play:
This graph can be used to show the potential for temperature falls if the albedo is brought back up to the previous level. The fall in albedo is causing the arctic temperature to rise. This analysis is based on the article published by Rudong Zhang, et al., which covers the years 1982 to 2014. The other years have been extrapolated from this data (no other data is available to me). It clearly shows that the drop in albedo is the main reason for the recent increase in temperature. This can be managed down, and it is time we got on with this!
What is the cause of the recent loss of Albedo?
The loss in albedo up to 1995 has been mainly due to the black carbon residual on the snow and ice. However, the dramatic loss of albedo since 1995 has not been directly caused by black carbon. Instead, it has been mainly caused by high rain falling in the arctic, with rain often replacing snow, as indicated in a report by Zhang, cited above. The higher temperatures themselves are a tipping point. The cold hard fact is that the recent reduction in albedo is due to the temperature in the arctic being more than 1.5°C above the pre-industrial temperature as a result of black carbon. This appears to be the tipping point for arctic temperatures. This would be a worthy subject for further study by climate scientists. We cannot stop the rise in the temperature in the artic without fixing the problem of black carbon.
Can we reduce black carbon in the arctic?
Soot mainly comes from coal fired electricity generation. This can be very effectively cut if we eliminate coal from electricity generation. However, this will have very bad effect on every society that follows this path if it currently is dependent on coal: it will lead to very expensive electricity. This has already been a significant cause of the increase in poverty in the UK. Yet it is preferable to the worst outcome, which is an acute shortage of electricity. This is currently being experienced in South Africa. What politician would want to be responsible for either outcome?
There is a method of cutting soot from coal-fired electricity without closing coal-fired generators. It is by installing exhaust controls on the chimneys of these power stations. This is beginning to be widely adopted, at least this is indicated by the bounce back of albedo in the last few years. The second method, is to convert the coal to gas before it is burnt. This is worth exploring if coal (and not nuclear) is a nation’s long-term preferred approach.
At least, the EU attempt to reduce the emissions from diesel engines appears to be reducing the emissions of unburnt diesel. Others will know the facts more certainly. The attempts to defeat the EU controls by major vehicle manufacturers is likely to have been quite counter-productive for their own purposes and for the world as a whole. Perhaps biodiesel that is designed to have lower unburnt diesel is another approach that could be a subject of research.
Conclusion
This subject is worthy of more detailed analysis than I have been able to provide. Let us hope that some of those with the skills required devote themselves to pursuing this matter. The arctic is worthy of more attention, and a cleaner and whiter arctic would be worthy goal on its own account, in addition to the likely climate payback for this effort.