By Dr. Sebastian Lüning and Prof. Fritz Vahrenholt
(German text translated/edited by P Gosselin)
In April 2012 the German online news daily WAZ reported with vigor:
Climate: air pollution leads to droughts and cyclones
Air pollution enhances droughts in Africa and cyclones over the Atlantic. This is the finding of British climate scientists. Historical climate events therefore can no longer be attributed to natural climate cycles. […] “We have to rethink: A number of historical climate events such as especially intense droughts in the Sahel region can no longer be attributed to natural climate fluctuations,’ Ben Booth and his colleagues of the Hadley Centre of the British Meteorological Office in Exeter wrote. Climate models up to now and also rules for aerosol emissions have to be changed in response to the new findings.”
Read more at derwesten.de.
This all concerns a paper by Booth et al. 2012. However their findings were met with substantial doubt from most fellow scientists (also see our blog posting “British Met Office claims aerosol overdose: I look at the world the way I want to see it“).
On June 6, 2016, the alarming model met its final demise. A team of scientists led by Jon Robson analyzed in the journal Nature Geoscience the climate development in the North Atlantic and were able to explain I full the temperature changes with the climate-internal Atlantic ocean cycles. The authors clearly explain that the aerosol hypothesis from Booth and his colleagues is thus invalid.
Yet, the German WAZ is silent on the new paper’s findings. Here is the abstract of the new paper by Robson et al. 2016:
A reversal of climatic trends in the North Atlantic since 2005
In the mid-1990s the North Atlantic subpolar gyre warmed rapidly1, which had important climate impacts such as increased hurricane numbers2 and changes to rainfall over Africa, Europe and North America3, 4. Evidence suggests that the warming was largely due to a strengthening of the ocean circulation, particularly the Atlantic Meridional Overturning Circulation1, 5, 6, 7. Since the mid-1990s direct and indirect measurements have suggested a decline in the strength of the ocean circulation8, 9, which is expected to lead to a reduction in northward heat transport10, 11. Here we show that since 2005 a large volume of the upper North Atlantic Ocean has cooled significantly by approximately 0.45 °C or 1.5 × 1022 J, reversing the previous warming trend. By analysing observations and a state-of-the-art climate model, we show that this cooling is consistent with a reduction in the strength of the ocean circulation and heat transport, linked to record low densities in the deep Labrador Sea9. The low density in the deep Labrador Sea is primarily due to deep ocean warming since 1995, but a long-term freshening also played a role. The observed upper ocean cooling since 2005 is not consistent with the hypothesis that anthropogenic aerosols directly drive Atlantic temperatures12.