Blog
Save
Email
Print
ShareAttribution of recent climate change is the effort to scientifically demonstrate which mechanisms are responsible for observed changes in the Earth's climate.
See also:
The endeavor centers on the observed changes over the last century and in particular over the last 50 years, when observations are best and human influence greatest.
The latest Intergovernmental Panel on Climate Change (IPCC) report concluded that, "Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations." The report defines "very likely" as a greater than 90% probability and represents the consensus of the scientific community. Over the past 150 years human activities have released increasing quantities of greenhouse gases into the atmosphere.
This has led to increases in mean global temperature or global warming.
Other human effects are relevant—for example, sulphate aerosols are believed to lead to cooling—and natural factors also contribute.
According to the historical temperature record of the last century, the Earth's near-surface air temperature has risen around 0.74 ± 0.18 °Celsius (1.3 ± 0.32 °Fahrenheit). An important question in current climate change research is over attribution of climate change to either natural/internal or human factors over the period of the instrumental record—from about 1860, and especially over the last 50 years.
In the 1995 second assessment report (SAR) the IPCC made the widely quoted statement that "The balance of evidence suggests a discernible human influence on global climate".
The phrase "balance of evidence" was used deliberately to suggest the (English) common-law standard of proof required in civil as opposed to criminal courts: not as high as "beyond reasonable doubt".
In 2001 the third assessment report (TAR) upgraded this by saying "There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities".
The 2007 fourth assessment report (AR4) report strengthened this and noted, "Discernible human influences now extend to other aspects of climate, including ocean warming, continental-average temperatures, temperature extremes and wind patterns.".
For more information about the topic Attribution of recent climate change, read the full article at Wikipedia.org, or see the following related articles:
Instrumental temperature record — The instrumental temperature record shows the fluctuations of the temperature of the atmosphere and the oceans since the invention of ... > read more
Geologic temperature record — This article is devoted to temperature changes in Earth's environment as determined from geologic evidence on multi-million to billion (109) year ... > read more
Greenhouse effect — The greenhouse effect is the process in which the emission of infrared radiation by the atmosphere warms a planet's surface. The name comes from an ... > read more
Climate — The climate is the weather averaged over a long period of time. Weather is the combination of events in the atmosphere and climate is the overall ... > read more
IPCC Report on Climate Change - 2007 — The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) is the fourth in a series of reports on climate change. Two of ... > read more
Global climate model — General Circulation Models (GCMs) are a class of computer-driven models for weather forecasting, understanding climate and projecting climate change, ... > read more
Temperature record of the past 1000 years — The temperature record of the past 1000 years describes the reconstruction of temperature for the last 1000 years on the Northern Hemisphere. A ... > read moreRecommend this page on Facebook, Twitter,
and Google +1:
Other bookmarking and sharing tools:
more 