In the April 20 Tribune Al Smith made claims about global warming including that Mann’s hockey stick graph representing climate warming has been discredited. While methods Mann used had been questioned, his results have been vindicated. A National Research Council study in 2006 corroborated Mann’s results. Mann and colleagues recently have done a new more detailed study giving the same conclusion. The US Senate Committee on Environment and Public works commissioned two studies on this issue with both studies resulting in the same conclusion. The hockey stick is sound. Sunspot inactivity was also mentioned by Smith as a cause of global cooling, but many scientific studies conclude that sunspots are unlikely to be a significant cause of global climate change. The energy Earth receives from the sun increases less than 0.1% from low to high sunspot activity. Without using greenhouse gas input, sunspots do not give the increases Earth has experienced. Smith also mentions that 2008 was cooler than 2007. That’s true, but 2008 was still a warm year for global temperature. The World Meteorological Organization reports that the trend for warming is still very much evident with the all years that have been warmer than 2008 being in the last 12 years. 2008 will likely rank as the 10^th warmest year on record. The slight dip in the mean global temperature is likely due to a La Niña that developed late in 2007. Those wanting more information can check these claims on the internet.

Ron Mathsen