The extraordinary sequence of extreme weather events during the last 18 months is probably the worst run of natural disasters since 1816, when a huge volcanic eruption at Mt Tambora cooled the earth enough to cause the famous “year without a summer“, according to a powerful blog post by Weather Underground founder Jeff Masters. He runs through the list, giving details of each:
- Earth’s hottest year on record
- Most extreme winter Arctic atmospheric circulation on record
- Arctic sea ice: lowest volume on record, 3rd lowest extent
- Record melting in Greenland, and a massive calving event
- Second most extreme shift from El Niño to La Niña
- Second worst coral bleaching year
- Wettest year over land
- Amazon rainforest experiences its 2nd 100-year drought in 5 years
- Global tropical cyclone activity lowest on record
- A hyperactive Atlantic hurricane season: 3rd busiest on record
- A rare tropical storm in the South Atlantic
- Strongest storm in Southwestern U.S. history
- Strongest non-coastal storm in U.S. history
- Weakest and latest-ending East Asian monsoon on record
- No monsoon depressions in India’s Southwest Monsoon for 2nd time in 134 years
- The Pakistani flood: most expensive natural disaster in Pakistan’s history
- The Russian heat wave and drought: deadliest heat wave in human history
- Record rains trigger Australia’s most expensive natural disaster in history
- Heaviest rains on record trigger Colombia’s worst flooding disaster in history
- Tennessee’s 1-in-1000 year flood kills 30, does $2.4 billion in damage
Masters argument is straightforward:
…it is highly improbable that the remarkable extreme weather events of 2010 and 2011 could have all happened in such a short period of time without some powerful climate-altering force at work. The best science we have right now maintains that human-caused emissions of heat-trapping gases like CO2 are the most likely cause of such a climate-altering force.
There’s more heat accumulating in the system, and more water vapour in the atmosphere to drive weather events.
A naturally extreme year, when embedded in such a changed atmosphere, is capable of causing dramatic, unprecedented extremes like we observed during 2010 and 2011. That’s the best theory I have to explain the extreme weather events of 2010 and 2011–natural extremes of El Niño, La Niña and other natural weather patterns combined with significant shifts in atmospheric circulation and the extra heat and atmospheric moisture due to human-caused climate change to create an extraordinary period of extreme weather.
However Masters doesn’t think that this sort of weather is the new normal — at least not yet — but it does suggest where we may be heading in 20-30 years time:
…the ever-increasing amounts of heat-trapping gases humans are emitting into the air puts tremendous pressure on the climate system to shift to a new, radically different, warmer state, and the extreme weather of 2010 – 2011 suggests that the transition is already well underway.
You don’t have to be an alarmist to find that alarming.
[Update: 30/6: The Guardian turns Masters' list into a slideshow of compelling images.]