Global warming scientific definition
The phrase refers to the documented historical warming of the Earth's surface based upon worldwide temperature records that have been maintained by humans since the 1880s. The term global warming is often used synonymously with the term climate change, but the two terms have distinct meanings. Global warming is the combined result of anthropogenic (human-caused) emissions of greenhouse gases and changes in solar irradiance, while climate change refers to any change in the state of the climate that can be identified by changes in the average and/or the variability of its properties (e.g., temperature, precipitation), and that persists for an extended period, typically decades or longer.
According to the World Meteorological Organization (WMO), the decade of the 2000s (2000–2009) is the warmest on record. The global mean surface temperature for 2009 is currently estimated at 0.44°C/0.79°F above the 1961-1990 annual average of 14.00°C/57.20°F. WMO states that in 2009 above-normal temperatures were recorded in most parts of the continents. Only North America (United States and Canada) experienced conditions that were cooler than average.
- global land and ocean annual surface temperatures through December tied with 2006 as the fifth warmest on record as +0.56°C (+1.01°F) above the twentieth century average
- the 2000-2009 decade is the warmest on record, with an average global surface temperature of 0.54°C (0.96°F) above the 20th century average,
- ocean surface temperatures (through December) tied with 2002 and 2004 as the fourth warmest on record, at 0.48°C (0.86°F) above the 20th century average, and
- and surface temperatures through December tied with 2003 as the seventh warmest on record, at 0.77°C (1.39°F) above the 20th century average.
The NCDC's Preliminary State of the Climate Global Analysis Annual Report of 2009 states that:
- "the years 2001 through 2008 each rank among the ten warmest years of the 130-year (1880-2009) record and 2009 was no exception, " and that
- "during the past century, global surface temperatures have increased at a rate near 0.06°C/decade (0.11°F/decade), but this trend has increased to a rate of approximately 0.16°C/decade (0.29°F/decade) during the past 30 years".
What is the scientific definition for global warming?
Scientists use "global warming" in a precise way, to mean "a tendency for the globe to warm over a given period".