sunsettommy
04-28-2006, 09:32 PM
From CLIMATE SCIENCE,
April 27, 2006
What Fraction of Global Warming is Due to the Radiative Forcing of Increased Atmospheric Concentrations of CO2? (http://climatesci.atmos.colostate.edu/2006/04/27/what-fraction-of-global-warming-is-due-to-the-radiative-forcing-of-increased-atmospheric-concentrations-of-co2/)
Filed under: Climate Change Forcings (http://climatesci.atmos.colostate.edu/category/climate-change-forcings/), Q & A on Climate Science (http://climatesci.atmos.colostate.edu/category/q-a-on-climate-science/) — Roger Pielke Sr. @ 7:32 am
This is a long weblog. The bottom line conclusions are written here to motivate reading the entire weblog.
CONCLUSIONS:
1. The primary focus on carbon dioxide inappropriately deemphasizes the first order importance of the other climate system heat system forcings (both cooling and warming forcings), as well as does not address the spatially complex, and incompletely understood, actual pattern of global climate system heat changes.
2. Attempts to significantly influence regional and local-scale climate based on controlling CO2 emissions alone is an inadequate policy for this purpose.
A starting point for the assessment of the relative fraction of global warming that is attributable to the radiative forcing of CO2 is the Summary Figure from the 2002 IPCC report (see (http://darwin.nap.edu/books/0309095069/html/3.html)). Clearly, according to their analysis, in comparing the change of radiative forcing since pre-industrial times until the present as estimated from the IPCC summary figure, the well-mixed greenhouse gases dominate the forcings which cause warming (about a 2.4 Watts per meter squared difference between these two time periods), of which about 1.4 Watts per meter squared is from CO2. Other warming forcings that they include, if the mean value plotted is used, are black carbon from burning fossil fuels (about 0.2 Watts per meter squared), tropospheric ozone (about 0.3 Watts per meter squared), and solar (about 0.25 Watts per meter squared).
Using these values about 58% of the radiative forcing of the well-mixed greenhouse gases results from CO2, and about 48% of the warming human-caused climate forcings result from the radiative forcing of CO2.
The following extracts from research studies reduce the relative contribution of the radiative forcing of CO2 as reported in the 2002 IPCC Report, as summarized above. These studies report the following,
“NASA scientists have found that a major form of global air pollution involved in summertime “smog” has also played a significant role in warming the Arctic……According to this new research, ozone was responsible for one-third to half of the observed warming trend in the Arctic during winter and spring. Ozone is transported from the industrialized countries in the Northern Hemisphere to the Arctic quite efficiently during these seasons. ”
(see). (http://climatesci.atmos.colostate.edu/2006/03/14/another-major-non-co2-climate-forcing-of-global-warming/)
”Even within the well-mixed greenhouse gas forcings, there are new complications. Drew Shindell and colleagues, as reported in Pollution Online found that, ’According to new calculations, the impacts of methane on climate warming may be double the standard amount attributed to the gas. The new interpretations reveal methane emissions may account for a third of the climate warming from well-mixed greenhouse gases between the 1750s and today. The IPCC report, which calculates methane’s affects once it exists in the atmosphere, states that methane increases in our atmosphere account for only about one sixth of the total effect of well-mixed greenhouse gases on warming. ’” (see). (http://climatesci.atmos.colostate.edu/2006/01/12/more-complications-on-quantifying-the-radiative-effects-of-well-mixed-greenhouse-gases/)
Moreover, from the 2006 Nature paper “Methane emissions from terrestrial plants under aerobic conditions (http://www.nature.com/nature/journal/v439/n7073/abs/nature04420.html)” by Keppler et al,
” If our measurements are typical for short-lived biomass and scaled on a global basis, we estimate a methane source strength of 62–236 Tg yr-1 for living plants and 1–7 Tg yr-1 for plant litter (1 Tg = 1012 g). We suggest that this newly identified source may have important implications for the global methane budget and may call for a reconsideration of the role of natural methane sources in past climate change.”
“A recent study by the CERES Science Team has added to the uncertainty associated with the contributions of climate forcings to global warming by finding that for the period 2000-2004, their assessment of the shortwave albedo decreased by 0.0015 which corresponds to an extra 0.5 Watts per meter squared of radiative imbalance according to their assessment. (see (http://climatesci.atmos.colostate.edu/2005/08/29/response-to-andy-revkin%e2%80%99s-science-question-of-august-26-2005-2/))
“Deposition of BC aerosols over snow-covered areas can result in changes to the surface albedo (Chylek et al. 1983). Further reductions in albedo occur due to the enhanced melting that accompanies the heating of absorbing soot particles in snow. Chylek et al. (1983) estimate this enhancement to be up to a factor of ten in the rate of melting. Recent model results indicate radiative forcings of +0.3 W m−2 in the Northern Hemisphere associated with albedo effects of soot on snow and ice (Hansen and Nazarenko 2004).” (see (http://climatesci.atmos.colostate.edu/2005/08/29/response-to-andy-revkin%e2%80%99s-science-question-of-august-26-2005-2/))
We can summarize these
(you can read the summary here)
http://climatesci.atmos.colostate.edu/2006/04/27/what-fraction-of-global-warming-is-due-to-the-radiative-forcing-of-increased-atmospheric-concentrations-of-co2/
It appears that CO2 is an overrated greenhouse gas.I long have been claiming.
It also appears that the Suns role in the current global warming is getting a bigger share of the attention.
Ozone pollution is now a bigger fish to fry for the cold regions.
He he he......
April 27, 2006
What Fraction of Global Warming is Due to the Radiative Forcing of Increased Atmospheric Concentrations of CO2? (http://climatesci.atmos.colostate.edu/2006/04/27/what-fraction-of-global-warming-is-due-to-the-radiative-forcing-of-increased-atmospheric-concentrations-of-co2/)
Filed under: Climate Change Forcings (http://climatesci.atmos.colostate.edu/category/climate-change-forcings/), Q & A on Climate Science (http://climatesci.atmos.colostate.edu/category/q-a-on-climate-science/) — Roger Pielke Sr. @ 7:32 am
This is a long weblog. The bottom line conclusions are written here to motivate reading the entire weblog.
CONCLUSIONS:
1. The primary focus on carbon dioxide inappropriately deemphasizes the first order importance of the other climate system heat system forcings (both cooling and warming forcings), as well as does not address the spatially complex, and incompletely understood, actual pattern of global climate system heat changes.
2. Attempts to significantly influence regional and local-scale climate based on controlling CO2 emissions alone is an inadequate policy for this purpose.
A starting point for the assessment of the relative fraction of global warming that is attributable to the radiative forcing of CO2 is the Summary Figure from the 2002 IPCC report (see (http://darwin.nap.edu/books/0309095069/html/3.html)). Clearly, according to their analysis, in comparing the change of radiative forcing since pre-industrial times until the present as estimated from the IPCC summary figure, the well-mixed greenhouse gases dominate the forcings which cause warming (about a 2.4 Watts per meter squared difference between these two time periods), of which about 1.4 Watts per meter squared is from CO2. Other warming forcings that they include, if the mean value plotted is used, are black carbon from burning fossil fuels (about 0.2 Watts per meter squared), tropospheric ozone (about 0.3 Watts per meter squared), and solar (about 0.25 Watts per meter squared).
Using these values about 58% of the radiative forcing of the well-mixed greenhouse gases results from CO2, and about 48% of the warming human-caused climate forcings result from the radiative forcing of CO2.
The following extracts from research studies reduce the relative contribution of the radiative forcing of CO2 as reported in the 2002 IPCC Report, as summarized above. These studies report the following,
“NASA scientists have found that a major form of global air pollution involved in summertime “smog” has also played a significant role in warming the Arctic……According to this new research, ozone was responsible for one-third to half of the observed warming trend in the Arctic during winter and spring. Ozone is transported from the industrialized countries in the Northern Hemisphere to the Arctic quite efficiently during these seasons. ”
(see). (http://climatesci.atmos.colostate.edu/2006/03/14/another-major-non-co2-climate-forcing-of-global-warming/)
”Even within the well-mixed greenhouse gas forcings, there are new complications. Drew Shindell and colleagues, as reported in Pollution Online found that, ’According to new calculations, the impacts of methane on climate warming may be double the standard amount attributed to the gas. The new interpretations reveal methane emissions may account for a third of the climate warming from well-mixed greenhouse gases between the 1750s and today. The IPCC report, which calculates methane’s affects once it exists in the atmosphere, states that methane increases in our atmosphere account for only about one sixth of the total effect of well-mixed greenhouse gases on warming. ’” (see). (http://climatesci.atmos.colostate.edu/2006/01/12/more-complications-on-quantifying-the-radiative-effects-of-well-mixed-greenhouse-gases/)
Moreover, from the 2006 Nature paper “Methane emissions from terrestrial plants under aerobic conditions (http://www.nature.com/nature/journal/v439/n7073/abs/nature04420.html)” by Keppler et al,
” If our measurements are typical for short-lived biomass and scaled on a global basis, we estimate a methane source strength of 62–236 Tg yr-1 for living plants and 1–7 Tg yr-1 for plant litter (1 Tg = 1012 g). We suggest that this newly identified source may have important implications for the global methane budget and may call for a reconsideration of the role of natural methane sources in past climate change.”
“A recent study by the CERES Science Team has added to the uncertainty associated with the contributions of climate forcings to global warming by finding that for the period 2000-2004, their assessment of the shortwave albedo decreased by 0.0015 which corresponds to an extra 0.5 Watts per meter squared of radiative imbalance according to their assessment. (see (http://climatesci.atmos.colostate.edu/2005/08/29/response-to-andy-revkin%e2%80%99s-science-question-of-august-26-2005-2/))
“Deposition of BC aerosols over snow-covered areas can result in changes to the surface albedo (Chylek et al. 1983). Further reductions in albedo occur due to the enhanced melting that accompanies the heating of absorbing soot particles in snow. Chylek et al. (1983) estimate this enhancement to be up to a factor of ten in the rate of melting. Recent model results indicate radiative forcings of +0.3 W m−2 in the Northern Hemisphere associated with albedo effects of soot on snow and ice (Hansen and Nazarenko 2004).” (see (http://climatesci.atmos.colostate.edu/2005/08/29/response-to-andy-revkin%e2%80%99s-science-question-of-august-26-2005-2/))
We can summarize these
(you can read the summary here)
http://climatesci.atmos.colostate.edu/2006/04/27/what-fraction-of-global-warming-is-due-to-the-radiative-forcing-of-increased-atmospheric-concentrations-of-co2/
It appears that CO2 is an overrated greenhouse gas.I long have been claiming.
It also appears that the Suns role in the current global warming is getting a bigger share of the attention.
Ozone pollution is now a bigger fish to fry for the cold regions.
He he he......