- Banned
- #1
Attribution of recent climate change - Wikipedia, the free encyclopedia
"Attribution of recent climate change is the effort to scientifically ascertain mechanisms responsible for recent changes observed in the Earth's climate. The effort has focused on changes observed during the period of instrumental temperature record, when records are most reliable; particularly on the last 50 years, when human activity has grown fastest and observations of the troposphere have become available."
The three dominant factors affecting the Earth's temperature are the dramatically increased levels of greenhouse gases, the changes to the surface from deforestation and melting snow and ice, and the presence of aerosols from various natural and synthetic (ie, anthropogenic) sources.
ibid
"Multiple lines of evidence support attribution of recent climate change to human activities:[4]
o A basic physical understanding of the climate system: greenhouse gas concentrations have increased and their warming properties are well-established.[4]
o Historical estimates of past climate changes suggest that the recent changes in global surface temperature are unusual.[4]
o Computer-based climate models are unable to replicate the observed warming unless human greenhouse gas emissions are included.[4]
o Natural forces alone (such as solar and volcanic activity) cannot explain the observed warming.[4]"
Reference 4 is US EPA, OAR, Climate Change Division (December 2009), Endangerment and Cause or Contribute Findings for Greenhouse Gases under Section 202(a) of the Clean Air Act: Climate Change: US EPA (PDF), Press release: EPA's Final Endangerment Finding: Climate Change Facts. Docket ID EPA-HQ-OAR-2009-0171.
Here's an interesting graphic. This is the output of a COMPUTER MODEL (ALERT, all you deniers get your hackles up). The model summed the noted forcing factors (solar, volcanic, sulfates, ozone and greenhouse gases) to come up with a total forcing. This is shown against the observed temperature trend (note the decent fit those of you that keep screaming the models don't work).
Numerous lines of evidence connect these factors to human activities and these factors to the observed temperature increases. It may be difficult to proceed beyond this point, however, as unlike the deniers here, all the reasonable, objective articles on this topic assume that global warming has been taking place and that the Greenhouse Effect is real. Lacking agreement on those points from a number of the folks around here is quite a wrench in the works. However, we (the folks who accept mainstream science) have spent far more than enough time attempting to convince the deniers here of the reality of these two points. I intend to proceed as if the audience here had reasonable intelligence and will treat global warming and the Greenhouse Effect as established facts, whether or not the audience concurs. I will do my best not to get drawn off debating whether or not the sun will rise tomorrow.
Human activity: the combustion of fossil fuels and deforestation are the primary cause of the global warming we have experienced over the last 150 years. That warming presents a real threat to the human species.
"Attribution of recent climate change is the effort to scientifically ascertain mechanisms responsible for recent changes observed in the Earth's climate. The effort has focused on changes observed during the period of instrumental temperature record, when records are most reliable; particularly on the last 50 years, when human activity has grown fastest and observations of the troposphere have become available."
The three dominant factors affecting the Earth's temperature are the dramatically increased levels of greenhouse gases, the changes to the surface from deforestation and melting snow and ice, and the presence of aerosols from various natural and synthetic (ie, anthropogenic) sources.
ibid
"Multiple lines of evidence support attribution of recent climate change to human activities:[4]
o A basic physical understanding of the climate system: greenhouse gas concentrations have increased and their warming properties are well-established.[4]
o Historical estimates of past climate changes suggest that the recent changes in global surface temperature are unusual.[4]
o Computer-based climate models are unable to replicate the observed warming unless human greenhouse gas emissions are included.[4]
o Natural forces alone (such as solar and volcanic activity) cannot explain the observed warming.[4]"
Reference 4 is US EPA, OAR, Climate Change Division (December 2009), Endangerment and Cause or Contribute Findings for Greenhouse Gases under Section 202(a) of the Clean Air Act: Climate Change: US EPA (PDF), Press release: EPA's Final Endangerment Finding: Climate Change Facts. Docket ID EPA-HQ-OAR-2009-0171.
Here's an interesting graphic. This is the output of a COMPUTER MODEL (ALERT, all you deniers get your hackles up). The model summed the noted forcing factors (solar, volcanic, sulfates, ozone and greenhouse gases) to come up with a total forcing. This is shown against the observed temperature trend (note the decent fit those of you that keep screaming the models don't work).
Numerous lines of evidence connect these factors to human activities and these factors to the observed temperature increases. It may be difficult to proceed beyond this point, however, as unlike the deniers here, all the reasonable, objective articles on this topic assume that global warming has been taking place and that the Greenhouse Effect is real. Lacking agreement on those points from a number of the folks around here is quite a wrench in the works. However, we (the folks who accept mainstream science) have spent far more than enough time attempting to convince the deniers here of the reality of these two points. I intend to proceed as if the audience here had reasonable intelligence and will treat global warming and the Greenhouse Effect as established facts, whether or not the audience concurs. I will do my best not to get drawn off debating whether or not the sun will rise tomorrow.
Human activity: the combustion of fossil fuels and deforestation are the primary cause of the global warming we have experienced over the last 150 years. That warming presents a real threat to the human species.
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