This weeks climate science
Our take on the most interesting climate science papers published or in press this week – a lot of modelling going onâ?¦
2°C warming by the end of the 21st century likely to be unavoidable�
A new modelling study has found that the Earth’s average temperature will increase by at least 2°C by 2100, even using the lowest estimates of greenhouse gas emissions. The study utilises emissions scenarios which will be used in the IPCC’s 5th Assessment report, to be released in 2014. The researchers warn that in order to limit the increase to just 2°C by 2100 we would have to cut all human-induced CO2 emissions from now until 2050, and actively remove CO2 from the atmosphere towards the end of the 21st century.
… But we’ll still experience extreme cold spells.
In a separate study, a group of climate modellers has found that even though average global temperature will rise over the 21st century, extreme cold snaps will still persist, even towards the end of the century. Cold snaps are likely to be less frequent, but could be as severe and last as long as they do currently – even under higher greenhouse gas emissions scenarios. Auroop Ganguly of Oak Ridge National Laboratory, US, who conducted the study said:
“Our findings suggest that despite a general warming trend, regional preparedness for extreme cold events cannot be compromised even toward the end of the century.”
Reference: Kodra, E., Steinhaeuser, K. & Ganguly, A.R. (in press) Persisting cold extremes under 21st-century warming scenarios. Geophysical Research Letters. DOI: 10.1029/2011GL047103.
IPCC estimates of Greenland ice sheet melt are likely to be far too low.
Scientists have developed a new model that can simulate the physical processes occurring at the Greenland ice sheet. A study using the model under realistic greenhouse gas projections for the 21st century has determined possible future rates of ice mass loss from the ice sheet. The findings show that, by 2100, around 220 km of ice will be lost every year, far higher than the 50 – 100 km loss per year suggested in the IPCC AR4 report.
A similar picture is coming from scientists studying mountain glaciers, who have found that some glaciers in Patagonia are melting up to 100 times faster than at any time over the past 350 years. Such high rates of ice loss from both the Arctic ice sheet and mountain glaciers could have a big impact on sea level rise.
These findings come as the National Snow and Ice Data Centre (NSIDC) have released their most recent data about Arctic sea ice coverage. The data shows that the sea ice extent for March 2011 was the second lowest in the satellite record, and that air temperatures have been higher than normal.
Aircraft contrails contribute more to warming than aviation fuel
“Contrail cirrus” is the name given to clouds that are formed from the condensation trails (contrails) that develop behind aircraft. A new study has modelled the impact of contrail cirrus on climate change – and found that is has an even greater warming effect than the emissions from the fossil fuels used to power the aircraft.