Leaked new IPCC report focuses on increase of extreme weather events

IPCC report on extreme weatherThe image to the right wasn’t leaked, but neatly published in 2007 – the old IPCC report. It still does a good job explaining the logic.

Most damage [ecological, economical] of climate change is not a direct consequence of a shift in mean temperatures. It is the result of the shift of the entire normal distribution. Whether climate change is expressed as a rise in temperatures, or as changing precipitation patterns – it is at the extreme edges of the graph that the frequency of weather events suddenly multiplies dramatically.

Heat waves, extreme precipitation events and flooding or extreme droughts, are also what actually cause climate damage – for instance lower agricultural productivity (as during the extremely hot 2003 summer in Western Europe) or biodiversity decline at ecosystem levels ranging from aquatic desert systems to entire rainforest biomes.

New report

The new IPCC publication on extreme weather is due to appear in three weeks time. Great thing about it is that it not only looks into the future, but also in the past, trying to explain recent events like the extremely hot US summer of 2011. We’ll give it a proper read then and promise to get back to you.

Associated Press says it has obtained a draft summary – but has not shared that document. The below numbers are therefore derived from the AP news release:

  • 99% there will be more extreme heat, and less extreme cold
  • Heat waves could peak as much as 5 degrees [we suppose that’s Fahrenheit, so that’s 2.8 degrees Celsius] hotter by 2050 and even 9 degrees [5 degrees Celsius] hotter by the end of the century.
  • There is a 2-in-3 probability that climate extremes have already worsened because of man-made greenhouse gases
  • Russian heat wave of 2010 has strong connection to climate change – 80% chance it would not have happened without it. [We wonder: would that in turn also connect part of the Pakistan monsoon floods of 2010 to climate change?]
  • Hurricanes and tropical cyclones are likely to get stronger in wind speeds – but may decrease in frequency.

We’ll especially do our bests to come to grips with that last bullet point – as it is one of the most complicated connections between climatology and meteorology – and what may go for Carribean and Gulf of Mexico hurricanes may not apply to Asian cyclones and typhoons.

© Rolf Schuttenhelm | www.bitsofscience.org

Comments are closed.