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Scientists develop new approach to support future climate projections
Last edited Thu Nov 29, 2012, 04:38 PM - Edit history (1)
http://www.southampton.ac.uk/mediacentre/news/2012/nov/12_206.shtml[font face=Serif][font size=5]Scientists develop new approach to support future climate projections [/font]
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29 November 2012
[font size=3]Scientists have developed a new approach for evaluating past climate sensitivity data to help improve comparison with estimates of long-term climate projections developed by the Intergovernmental Panel on Climate Change (IPCC).
The sensitivity of global temperature to changes in the Earth’s radiation balance (climate sensitivity) is a key factor for understanding past natural climate changes as well as potential future climate change.
Many palaeoclimate studies have measured natural climate changes to calculate climate sensitivity, but a lack of consistent methodologies produced a wide range of estimates as to the exact value of climate sensitivity, which hindered results.
Now a team of international scientists including Eelco Rohling, Professor of Ocean and Climate Change at the University of Southampton, have developed a more consistent definition of climate sensitivity in prehistoric times. When the scientists evaluated previously published estimates for climate sensitivity from a variety of geological episodes over the past 65 million years, they found that the estimates varied over a very wide range of values, with some very high values among them (high values would imply a very strong temperature response to a change in radiative forcing, for example, due to CO2 increase).
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Ref: 12/206
29 November 2012
[font size=3]Scientists have developed a new approach for evaluating past climate sensitivity data to help improve comparison with estimates of long-term climate projections developed by the Intergovernmental Panel on Climate Change (IPCC).
The sensitivity of global temperature to changes in the Earth’s radiation balance (climate sensitivity) is a key factor for understanding past natural climate changes as well as potential future climate change.
Many palaeoclimate studies have measured natural climate changes to calculate climate sensitivity, but a lack of consistent methodologies produced a wide range of estimates as to the exact value of climate sensitivity, which hindered results.
Now a team of international scientists including Eelco Rohling, Professor of Ocean and Climate Change at the University of Southampton, have developed a more consistent definition of climate sensitivity in prehistoric times. When the scientists evaluated previously published estimates for climate sensitivity from a variety of geological episodes over the past 65 million years, they found that the estimates varied over a very wide range of values, with some very high values among them (high values would imply a very strong temperature response to a change in radiative forcing, for example, due to CO2 increase).
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http://www.awi.de/en/news/press_releases/detail/item/new_approach_allows_past_data_to_be_used_to_improve_future_climate_projections/?cHash=0d43dd0015899cd93700b646ea50c055
[font face=Serif]29. November 2012: [font size=5]New approach allows past data to be used to improve future climate projections[/font]
[font size=4]Bremerhaven, 27 November 2012. Climate scientists are still grappling with one of the main questions of modern times: how high will global temperatures rise if the atmospheric concentration of carbon dioxide doubles. Many researchers are now turning to the past because it holds clues to how nature reacted to climate change before the anthropogenic impact. The divergent results of this research, however, have made it difficult to make precise predictions about the impact of increased carbon dioxide on future warming. An international team of scientists have evaluated previously published estimates and assigned them consistent categories and terminology. This process should assist in limiting the range of estimates and make it easier to compare data from past climate changes and projections about future warming. The group has presented its new method in the current edition of the journal Nature.[/font]
[font size=3]The research group summarized, classified and compared data from more than 20 studies to make a potential prognosis about the expected future rise in the world’s temperature. In these palaeoclimate studies climate sensitivity has been reconstructed on the basis of data derived from ice and sediment core. Climate sensitivity is a key parameter in the study of climate change. It describes the rise of the mean temperature of the earth’s surface due to changes in the climate system. Specifically, its value represents the increase in global temperatures calculated by climate models, if the carbon dioxide content in the atmosphere doubles. Here, models were initialised with pre-industrial carbon dioxide concentrations.
The team was then faced with the challenge of comparing the assembled studies. Each study spoke of “climate sensitivity”, but not all took the same factors into account. “We had to elaborate all the different assumptions and uncertainties, such as which studies look exclusively at carbon dioxide and which considered other greenhouse gases such as methane or the effect of reflection, the so called albedo, from ice surfaces. Only then could we compare the data. We also calculated the climate sensitivity data if we only considered greenhouse gases like carbon dioxide or added in albedo”, explained Dr Peter Köhler, one of the article’s main authors and climatologist at the Alfred Wegener Institute for Polar and Marine Research, part of the Helmholtz Association.
The research group was able to use its new method to differentiate ten different kinds of climate sensitivity. In a second phase of the project, they then worked on devising consistent terminology and concrete definitions. The new classification system should prevent future researchers from publishing widely divergent estimates of climate sensitivity based on differing assumptions. “Ideally, it should be clear from the start of a study what kind of climate sensitivity is being addressed. The factors considered by the researchers to be driving temperature change should be clear from the language used. Our terminology offers a conceptual framework to calculate climate sensitivity based on past climate data. We hope that this will improve evaluation of future climate projections”, adds Köhler.
…[/font][/font]
[font size=4]Bremerhaven, 27 November 2012. Climate scientists are still grappling with one of the main questions of modern times: how high will global temperatures rise if the atmospheric concentration of carbon dioxide doubles. Many researchers are now turning to the past because it holds clues to how nature reacted to climate change before the anthropogenic impact. The divergent results of this research, however, have made it difficult to make precise predictions about the impact of increased carbon dioxide on future warming. An international team of scientists have evaluated previously published estimates and assigned them consistent categories and terminology. This process should assist in limiting the range of estimates and make it easier to compare data from past climate changes and projections about future warming. The group has presented its new method in the current edition of the journal Nature.[/font]
[font size=3]The research group summarized, classified and compared data from more than 20 studies to make a potential prognosis about the expected future rise in the world’s temperature. In these palaeoclimate studies climate sensitivity has been reconstructed on the basis of data derived from ice and sediment core. Climate sensitivity is a key parameter in the study of climate change. It describes the rise of the mean temperature of the earth’s surface due to changes in the climate system. Specifically, its value represents the increase in global temperatures calculated by climate models, if the carbon dioxide content in the atmosphere doubles. Here, models were initialised with pre-industrial carbon dioxide concentrations.
The team was then faced with the challenge of comparing the assembled studies. Each study spoke of “climate sensitivity”, but not all took the same factors into account. “We had to elaborate all the different assumptions and uncertainties, such as which studies look exclusively at carbon dioxide and which considered other greenhouse gases such as methane or the effect of reflection, the so called albedo, from ice surfaces. Only then could we compare the data. We also calculated the climate sensitivity data if we only considered greenhouse gases like carbon dioxide or added in albedo”, explained Dr Peter Köhler, one of the article’s main authors and climatologist at the Alfred Wegener Institute for Polar and Marine Research, part of the Helmholtz Association.
The research group was able to use its new method to differentiate ten different kinds of climate sensitivity. In a second phase of the project, they then worked on devising consistent terminology and concrete definitions. The new classification system should prevent future researchers from publishing widely divergent estimates of climate sensitivity based on differing assumptions. “Ideally, it should be clear from the start of a study what kind of climate sensitivity is being addressed. The factors considered by the researchers to be driving temperature change should be clear from the language used. Our terminology offers a conceptual framework to calculate climate sensitivity based on past climate data. We hope that this will improve evaluation of future climate projections”, adds Köhler.
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http://dx.doi.org/10.1038/nature11574
