UN IPCC announces new definition of 'climate change,' no longer tied to human behavior, includes natural means, land use, & decades or longer duration

Tweet Citing "progress in science," UN global climate change policy announces a change in the definition of "climate change" from prior UN reports. The term is no longer tied to human behavior, now includes change via "natural processes" and "land use," and must persist for "decades or longer" or is not "climate change." (p.2)

11/19/11, "IPCC Introduces New 'Climate Change' Definition," GWPF

11/18/11, "First Joint Session of Working Groups I and II, IPCC SREX Summary for Policymakers"

"Definitions central to SREX

Core concepts defined in the SREX glossary (1) and used throughout the report include:

[Insert footnote 1 here: Reflecting the diversity of the communities involved in this assessment and in

• progress in science,

several of the definitions used in this Special Report differ in breadth or focus from those used in the AR4 and other IPCC reports].

Climate Change:

Climate change may be due to natural internal processes or external forcings, or to persistent anthropogenic changes in the composition of the atmosphere

• or in land use. ...
  

A change in the state of the climate that can be identified (e.g., by using statistical tests) by
changes in the mean and/or the variability of its properties and that

• persists for an extended period, typically
  
• decades or longer.

[Insert footnote 2: This definition differs from that in the United Nations Framework Convention on Climate Change (UNFCCC), where climate change is defined as, "a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods."

• The UNFCCC thus makes a distinction
  

between climate change attributable to human activities altering the atmospheric composition,

• and climate variability attributable to natural causes.]

Climate Extreme (extreme weather or climate event):

...For simplicity, both extreme weather events and extreme climate events are

• referred to collectively as "climate extremes."..."

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11/18/11, "Climate Change Weather Effects Unknown: IPCC Report," The Australian, via GWPF

"Great uncertainty remains about how much of an impact climate change will have on future extreme weather events, the world's leading climate scientists have found."...

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