Climate extemes papers Climate change information for adaptation: Climate trends and projected values for Canada 2010 to 2050 James P. Bruce - March 1, 2011 ICLR Research Paper Series - No. 50
Many people postpone action to adapt their businesses and management activities to the changing climate because of uncertainties about future climatic conditions. It is true that the range of projected futures becomes rather large by the end of the century. This is due to uncertainties about future greenhouse gas emissions and the differences in results from various global climate models.
However, for many purposes, planning horizons are less than a century and modelled results are not very divergent out to 2050. In addition, anthropogenic factors, i.e. greenhouse gas increases, have been overwhelmingly dominant in driving changes in global and large scale regional, climate since about 1970. They will continue to dominate in the coming 4 decades. Thus, trends that have been measured and observed in climate-related factors over the past 4 decades are likely to continue or possibly intensify somewhat in the next 40 years. When extension of such trends is similar to projections to 2050 by climate models, event greater confidence can be placed in the estimates of future climate.
The highest emission scenario is the closest to observed trends. Recent information on GHG concentrations, emissions and impacts lead to the view that climate change is advancing more rapidly than estimated earlier. Global atmospheric CO2 concentration increases averaged 1.6 ppm/year from 1970 to 2007, but 1.9 ppm/year from 2000 to 2007 (Levinson, 2008). From 1990 to 2000, the atmosphere’s CO2 increased at a rate of 3.1 gigatonnes carbon per year but from 2000 to 2008 the rate was 4.1gt C/year (IGBP, 2009).
At the same time the International Energy Agency in late 2007 reported that global energy use and greenhouse gas emissions have been rising very rapidly. It projects a 55% increase in world energy needs between 2005 and 2030 and a 57% increase in greenhouse gas emissions. This could be tempered by aggressive global efforts to reduce emissions, not evident to date. Of course, the recent economic downturn had a short term effect on this rate of change. It is estimated that in 2009 a reduction of about 1% in global emissions occurred, but 2010 emissions are again on a path to record highs.