Given present trends, CO2 concentration should increase from 280 ppm (pre-industrial), 355 ppm (current) to 560 ppm around 2050. This may cause a rise in mean global temperature of 1.5-4.5 degrees Celsius, and a rise in sea levels of 30-110 mm (due to thermal expansion of the oceans and to a lesser extent some melting of land ice). Canada and Siberia would benefit in terms of increased agricultural land, but there would be overall world net loss.