This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
ClimateClimate is usually defined as the average weather, is usually defined as the average weather, or more rigorously, as the statistical description in or more rigorously, as the statistical description in terms of the mean and variability of relevant terms of the mean and variability of relevant quantities over a period of time ranging from quantities over a period of time ranging from months to thousands or millions of years. months to thousands or millions of years.
What is climate change and variability?What is climate change and variability?Climate changeClimate change refers to a change in the state of the refers to a change in the state of the climate that can be identified (e.g., by using statistical climate that can be identified (e.g., by using statistical tests) by changes in the mean or variability of its tests) by changes in the mean or variability of its properties, and that persists for an extended period, properties, and that persists for an extended period, typically decades or longer.typically decades or longer.
Climate variabilityClimate variability refers to variations beyond refers to variations beyond individual weather events in the mean state and other individual weather events in the mean state and other statistics of the climate (such as standard deviations, the statistics of the climate (such as standard deviations, the occurrence of extremes, etc.) on all spatial and temporal occurrence of extremes, etc.) on all spatial and temporal scales. scales.
This includes “internal variability”.This includes “internal variability”.
What is detection and attribution?What is detection and attribution?
Detection Detection of climate changeof climate change is the process of is the process of demonstrating that climate has changed in some defined demonstrating that climate has changed in some defined statistical sense, without providing a reason for that statistical sense, without providing a reason for that change. change.
AttributionAttribution of causes of climate change is the process of of causes of climate change is the process of establishing the most likely causes for the detected establishing the most likely causes for the detected change with some defined level of confidence.change with some defined level of confidence.
Latitudinal Distribution of TrendsLatitudinal Distribution of Trends
Red:Red: All forcings, middle 90% of GCM range All forcings, middle 90% of GCM range
(58 simulations by 14 GCMs)(58 simulations by 14 GCMs)
Blue:Blue: Natural forcings only, middle 90% of GCM rangeNatural forcings only, middle 90% of GCM range
(19 simulations by 5 GCMs)(19 simulations by 5 GCMs)
Land & Ocean ChangesLand & Ocean Changes
IPCC:IPCC: Most global warming Most global warming very likelyvery likely due to increase in due to increase in anthropogenic GHG concentrationsanthropogenic GHG concentrations
Likely anthropogenic warming on continental scaleLikely anthropogenic warming on continental scale
Methods of Detection - Inferring ChangeMethods of Detection - Inferring Change
Are at least some of the scale factors Are at least some of the scale factors significantly different from zero?significantly different from zero? DETECTIONDETECTION
Is a forcing distinguishable from others? Is a forcing distinguishable from others? Can it (or some combination) explain Can it (or some combination) explain the observed pattern?the observed pattern?
Probability of extreme European summer temperatures(using the Hadley Centre GCM)
… … the the probabilityprobability (risk) of an occurrence can change due to (risk) of an occurrence can change due to external influences. external influences.