Since the start of the new century there has been no change in the world’s annual-mean temperature. Climate change deniers have seized upon this fact and our continuing addition of CO2 to the atmosphere with no effect, to support their view that human beings are not causing climate change and a temperature rise.
A new study entitled “Recent global-warming hiatus tied to equatorial Pacific surface cooling” published in the September 19, 2013 issue of Nature magazine, attributes the pause in the climate change temperature increase to natural causes. The research report prepared by the Scripps Institution of Oceanography at the University of California, San Diego states, “Our results show that the current hiatus is part of natural climate variability, tied specifically to a La-Niña-like decadal cooling.”
The researchers successfully recreated our last decade of experience by altering climate models to reflect increased greenhouse gas concentrations, aerosol concentration and solar cycle changes. When they added the known rise in sea-surface temperatures in the equatorial Pacific, their model predicted as a normal climate variation what we are experiencing with a correlation coefficient of r=0.97 for the period of 1970 to 2012.
Contributing to the confusion about the stability of the world annual-mean temperature is the record heat waves in Russia in 2010, the U.S. in 2012 and Arctic sea ice reaching record lows in 2007 and 2012. In addition we have seen record rains in Australia. So much water has been deposited on Australia and absorbed into the soil that the overall mean global sea level has fallen by 7 mm. When measuring the Earth’s gravity field around Australia there was a parallel increase in the mass of water retained on land.
In the meantime, the U.N. Intergovernmental Panel on Climate Change (IPCC) is releasing its most recent assessment. Their report raises the level of confidence of a human caused climate change to 95% probability (up from 90%) and changes descriptors of the new likelihood to “extremely likely” (from “very likely”). The report continues, “There is high confidence that this has warmed the ocean, melted snow and ice, raised global mean sea level, and changed some climate extremes.”
Early circulation of drafts of this report have in part set the stage for new G20 agreements to curb emissions of hydrofluorocarbons (HFCs). On June 8, 2013 the U.S. and China agreed to the progressive elimination of HFCs.
Readers will recall an earlier post on January 4, 2013 on this site entitled “Are We Trading Greenhouse Gas for Ozone?” in which we identified that HFCs were protective of ozone but very powerful greenhouse cases that contributed to climate change. HFCs are many more times more damaging than carbon dioxide to the atmosphere. In addition the article cited the significant increased production and sale of air conditioners in China and India that use the HFCs as their coolant. For a reprise of that article see http://www.iamaguardian.com/category/protect/ozone-depletion .
In January 1, 1989 the Montreal Protocol went into effect. This was an international agreement to ban substances that destroy the ozone layer of the planet. The central purpose of the agreement was to progressively eliminate chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) that are very damaging to our ozone layer. The assumption was that hydrofluorocarbons (HFCs) could be substituted for example in air conditioning and refrigeration and would not damage the ozone. At the time there was no climate change or concerns about greenhouse gases. The recent agreement corrects that oversight.
Finally, a new study reported in the August 2013 issue of Science magazine and other articles describe the process that is accelerating the movement of ice sheets and glaciers. Scientists report that hotter temperatures are melting the surface snow and ice with the water draining down to the bedrock below. This new layer of water between the soil and the ice sheets and glaciers acts as a lubricant that increases the speed of movement of the ice. The faster the movement, the sooner they calve and/or break apart. All of which shortens the lifetime of large bodies of ice that have been in place for centuries.
Use the following links to obtain additional information or access source documents: