28. The Future

The anthropogenic factors causing Earth’s climate and environment to change include increases in atmospheric greenhouse gas concentrations, changes in land use, urbanization, mining, and other alterations ultimately resulting from the growth of the human population. Projections of future change by the Intergovernmental Panel on Climate Change (IPCC) are very conservative, and modern trends generally exceed their ‘worst case’ scenarios from their 2007 report. Although many countries are making efforts to reduce their greenhouse gas emissions, a few countries, most notably the United States refuse to participate. It is recognized that there are tipping points in the climate system. Unfortunately, a tipping point cannot be identified with certainty until one is far enough past it so that there is no possibility of return. For me the great Arctic ice meltback of 2007 indicated we had gone past a tipping point. This event wasn’t expected until the end of the 21st century. A number of changes are accelerating: melting of the Greenland ice sheet, breakup of the ice shelves of the Antarctic, and slowing of the thermohaline circulation. Other changes are occurring with El Niño and the Southern Oscillation, the Indian summer monsoon, in the Sahara and Sahel, and in Amazonia. Changes in the boreal forest, tundra, and permafrost are beginning to appear. Sea level rise is accelerating. The potential release of methane from clathrates and a possible die-off of marine plankton would be catastrophic. Mother Nature may impose her own remedy.