Sunday, May 29, 2011

Beyond 2 Degrees Celsius -PDF

Implications of NASA/GISS updates for the Earth energy balance, global temperatures, ice melt and sea level rise.

The Earth energy balance—namely the difference between energy/heat absorbed by the Earth from solar radiation and the energy/heat emitted back to space— estimated at +3.1 Watt/m2, equivalent to a +2.3 degrees C (based on climate sensitivity of 3C per doubling of CO2) (Hansen et al., 2011 [1]), is currently in part mitigated by the cooling effect of albedo-enhancing sulphur aerosols (~ -1.6 Watt/m2 = ~ -1.2C) emitted from fossil fuels and industry, which effectively act as a global geo-engineering process (Figure 1). Had it not been for this short-lived (few years-long) cooling effect the internationally agreed maximum temperature target of <2 degrees C would be transcended.

According to the IPCC AR4 (2007) [2] mean global land/ocean temperature since 1880 has risen by about +0.8C, which translates to more than +4C rise in the polar region of northern Canada, Greenland and Siberia [3] (Figure 2), triggering feedback-amplified ice melting accelerating between 2002 and 2010 [4] (Figure 3) and related sea level rise at a rate of 3.0+/-0.4 mm/year between 1993-2010 (Figure 4A). Melting of Arctic ice leading to increased evaporation can result in the advance of cold fronts into the north Atlantic. More >>>

Location: Cayman Islands