The term climate change is used to refer to changes in the Earth's climate. Generally, this is taken to regard changes in temperature, by monitoring averages, extremes, durations, and geographic coverages. "Climate change" can include "natural" changes but the primary concern and focus is on human activities that are contributing to global warming. "When scientists talk about the issue of climate change, their concern is about global warming caused by human activities."
Examples of climate change
In the August 30, 2005, Boston Globe article "Katrina's Real Name," Ross Gelbspan wrote:
- "When the year began with a two-foot snowfall in Los Angeles, the cause was global warming.
- "When 124-mile-an-hour winds shut down nuclear plants in Scandinavia and cut power to hundreds of thousands of people in Ireland and the United Kingdom, the driver was global warming.
- "When a severe drought in the Midwest dropped water levels in the Missouri River to their lowest on record earlier this summer, the reason was global warming. Note: "worst drought since 1988".
- "In July, when the worst drought on record triggered wildfires in Spain and Portugal and left water levels in France at their lowest in 30 years, the explanation was global warming.
- "When a lethal heat wave in Arizona kept temperatures above 110 degrees and killed more than 20 people in one week, the culprit was global warming.
- "And when the Indian city of Bombay (Mumbai) received 37 inches of rain in one day -- killing 1,000 people and disrupting the lives of 20 million others -- the villain was global warming."
A November 2010 Newsweek article summed up some of the extreme climate and weather events in 2009-10:
- 135 daily rainfall records were broken along the U.S. East Coast in September 2010 (Wilmington, N.C.: 19.7 inches over three days).
- 2010 beat 1998 as the hottest year on record, with 153 of the 1,218 U.S. weather stations recording their hottest summer since 1895.
- 2000–09 was the warmest decade on record.
- In August 2010, an ice island four times the size of Manhattan (260 sq km) broke off from a Greenland glacier.
- Moscow suffered a once-in-centuries heat wave, doubling average death rates to 700 people a day.
- One-fifth of Pakistan flooded, affecting 20 million people and killing nearly 2,000.
Calculating the effect of CO2 change on extreme weather
Climate scientists have long resisted wholly attributing weather events to climate change, but have developed a technique called “fractional risk attribution” to calculate how many times an extreme event should have occurred absent human interference. The technique uses mathematical models of how the atmosphere would behave before human activity raised carbon dioxide levels to 389 parts per million (it was 278 before the Industrial Revolution), plus data about ancient (“paleo”) climates and historical (more recent) weather. Climate scientists led by Peter Stott of the British Met Office analyzed the 2003 European heat wave, the highest temperatures for the area since the introduction of weather instruments (1851), and concluded that human activity could be attributed to 75 percent of the heat wave. Put another way, they estimated that human activity more than doubled the chance that it would happen, and found it was twice as likely to be human-caused than natural.
Reviewing the continued campaign by climate change skeptics, David McKnight, an associate professor at the University of New South Wales (Australia), notes that there several reasons why companies such as Exxon have had some success playing the global warming denial card. "First, the implications of the science are frightening. Shifting to renewable energy will be costly and disruptive. Second, doubt is an easy product to sell. Climate denial tells us what we all secretly want to hear. Third, science is portrayed as political orthodoxy rather than objective knowledge, a curiously postmodern argument," he writes. While the tobacco industry is often referred to as the template for the fossil fuel industry's campaign, McKnight argues that there is an important distinction. "There are no 'smoke-free areas' on the planet. Climate denial may turn out to be the world's most deadly PR campaign," he concludes. 
References and further reading
The links below present differing opinions regarding the extent and existence of various causes for climate change.
Documents & Reports
- United Nations Framework Convention on Climate Change (UNFCCC).
- Chris Mooney, "Some Like It Hot," Mother Jones, May/June 2005: "Forty public policy groups have this in common: They seek to undermine the scientific consensus that humans are causing the earth to overheat. And they all get money from ExxonMobil.
- Katharine M. Willett, Nathan P. Gillett, Philip D. Jones & Peter W. Thorne, "Attribution of observed surface humidity changes to human influence" Nature, Oct. 11, 2007. ("We identify a significant global-scale increase in surface specific humidity that is attributable mainly to human influence" (p. 710)).
Articles and resources
Related GEM.wiki articles
- U.S. Environmental Protection Agency, http://www.epa.gov/globalwarming/kids/gw.html
- Sharon Begley, "A Climate Whodunit: Science nails the blame game" Newsweek, Nov. 27, 2010.
- "The Climate Change Smoke Screen", Sydney Morning Herald, August 2, 2008
- Wikipedia help
- "Drought monitoring and early warning: concepts, progress and future challenges: Weather and climate information for sustainable agricultural development," World Meteorological Organization, ISBN 92-63-11006-9, 2006.