Graph of the day: weather extremes are on the rise

Why write a full news story when a single graph tells you everything: ‘unprecedented records in monthly mean temperature’ between 1900-2000 for 17 weather stations across the globe.

If you are a mathematical purist you may have disliked the title of our latest article about the relation between climate change and extreme weather events – which states weather extremes would lie ‘beyond’ Gaussian distribution. But we do hope you would agree the above graph – derived from a new Nature Climate Change publication by the Potsdam Institute for Climate Impact Research (PIK) – shows us we shouldn’t be overly theoretical about the theory anyway.

After all, there is a real world out there, where real things happen – like the European heat wave of 2003 and the Russian heat wave of 2010, extreme weather events that led to tens of thousands of lost human lives, billions of dollars of economic damage – and as whiplash hundreds of megatonnes of extra CO2 emissions from dried-out agricultural soils to forest fires, an increasingly significant positive climate feedback.

Heat waves, droughts, floods

The PIK researchers conclude that weather extremes are indeed on the rise – as a result of the global rise in average temperatures. Unsurprisingly the strongest correlation exists for temperature extremes (and therefore also droughts), and also many extreme rainfall events (in tropical regions often ENSO-state-dependent) result from the warming trend.

But don’t necessarily blame that tree that demolished your parked car on your own car’s exhaust fumes – that may just have been a lucky shot

The connection is less clear when it comes to severe storm events, the German climate researchers say.

This should not surprise us as the formation of for instance Atlantic hurricanes and Indian cyclones depends on many complicated climatic factors, including ENSO and MOC cycles, jet stream location, trade winds, local aerosol pollution and ocean warming, which of course lags behind atmospheric warming [which could mean less, not more convection over tropical storm trajectories in the open ocean].