Tuesday, April 21, 2009
Old Old Ships' Logs Show Temporary Global Warming in 1730s
http://www.theregister.co.uk/2008/08/04/ships_log_climate_change/
Old ships' logs show temporary global warming in 1730s
Records interrupted only by looting of treasure galleons
By Lewis Page
Posted in Environment, 4th August 2008 13:06 GMT
Free whitepaper – An improved architecture for high-efficiency, high-density data centers
A climate prof noted for data mining of archived ships' logs has produced further insights into global warming. Dr Dennis Wheeler of Sunderland Uni says his latest analysis shows sudden warming of the North Atlantic and Europe - much like that seen in recent times - during the 1730s.
This, Wheeler believes, shows that widespread rises in temperature of the kind recorded lately can be caused naturally. He thinks that human-caused carbon emissions are contributing to climate change now, but says it is unwise to link human emissions to specific events unless evidence is very strong.
“Global warming is a reality, but what our data shows is that climate science is complex and that it is wrong to take particular events and link them to CO2 emissions," Wheeler told (http://www.timesonline.co.uk/tol/news/environment/article4449527.ece) the Times at the weekend.
Wheeler's new 1730s temperature spike info comes from trawling through mountains of archived ship's logs. Royal Navy logbooks have been particularly valuable, both for this project and previous ones.
“British archives contain more than 100,000 Royal Navy logbooks from around 1670 to 1850 alone," says Wheeler. "They are a stunning resource.”
The new research, compiled by Wheeler and colleagues from the Met Office and other institutions, is to be published in the journal Climatic Change. The paper has already gained a good deal of ink in the UK media, generally referencing Admiral Nelson and Captain Cook for their zeal in keeping accurate records.
As neither Cook nor Nelson were at sea during the 1730s, this seems a bit unreasonable. Perhaps the most famous British naval officer active at the time was Captain (later Admiral) George Anson. Anson subsequently became a naval legend after his epic voyage round the world from 1740-44, during which he and his crew captured a Spanish treasure galleon in the Pacific - making the survivors who eventually got home to England rich men. Later, as an admiral, Anson also handed the French a massive kicking at Cape Finisterre and then became First Sea Lord - the head of the Navy.
During the 1730s - the period where Wheeler's sudden warming occurs - Captain Anson was at sea in the Atlantic, so it's likely that his logs form part of Wheeler's data set. However, it wasn't normal for warships to carry thermometers at the time, so much of the analysis draws on winds and the "consistent language" used by sea officers of the time, as well as European shore-based records. ®
Old ships' logs show temporary global warming in 1730s
Records interrupted only by looting of treasure galleons
By Lewis Page
Posted in Environment, 4th August 2008 13:06 GMT
Free whitepaper – An improved architecture for high-efficiency, high-density data centers
A climate prof noted for data mining of archived ships' logs has produced further insights into global warming. Dr Dennis Wheeler of Sunderland Uni says his latest analysis shows sudden warming of the North Atlantic and Europe - much like that seen in recent times - during the 1730s.
This, Wheeler believes, shows that widespread rises in temperature of the kind recorded lately can be caused naturally. He thinks that human-caused carbon emissions are contributing to climate change now, but says it is unwise to link human emissions to specific events unless evidence is very strong.
“Global warming is a reality, but what our data shows is that climate science is complex and that it is wrong to take particular events and link them to CO2 emissions," Wheeler told (http://www.timesonline.co.uk/tol/news/environment/article4449527.ece) the Times at the weekend.
Wheeler's new 1730s temperature spike info comes from trawling through mountains of archived ship's logs. Royal Navy logbooks have been particularly valuable, both for this project and previous ones.
“British archives contain more than 100,000 Royal Navy logbooks from around 1670 to 1850 alone," says Wheeler. "They are a stunning resource.”
The new research, compiled by Wheeler and colleagues from the Met Office and other institutions, is to be published in the journal Climatic Change. The paper has already gained a good deal of ink in the UK media, generally referencing Admiral Nelson and Captain Cook for their zeal in keeping accurate records.
As neither Cook nor Nelson were at sea during the 1730s, this seems a bit unreasonable. Perhaps the most famous British naval officer active at the time was Captain (later Admiral) George Anson. Anson subsequently became a naval legend after his epic voyage round the world from 1740-44, during which he and his crew captured a Spanish treasure galleon in the Pacific - making the survivors who eventually got home to England rich men. Later, as an admiral, Anson also handed the French a massive kicking at Cape Finisterre and then became First Sea Lord - the head of the Navy.
During the 1730s - the period where Wheeler's sudden warming occurs - Captain Anson was at sea in the Atlantic, so it's likely that his logs form part of Wheeler's data set. However, it wasn't normal for warships to carry thermometers at the time, so much of the analysis draws on winds and the "consistent language" used by sea officers of the time, as well as European shore-based records. ®
Monday, April 20, 2009
Talking Climate Change with Anthony Watts
http://townhall.com/Common/PrintPage.aspx?g=42662c1d-db76-4d02-ad93-8fff406c1a1b&t=c
Talking Climate Change with Anthony Watts
Bill Steigerwald
Monday, April 20, 2009
Anyone who regularly tunes into WattsUpWithThat.com, the popular climate-science blog operated by Anthony Watts, will never make fun of TV weathermen again. Watts - who was a TV meteorologist for 25 years - provides a steady diet of smart, always interesting and sometimes deeply complex scientific information and opinion about global climate change. Watts is also the founder of surfacestations.org, a project that for nearly two years has been quality-checking each of the 1,200-plus weather stations of the U. S. Historical Climate Network (USHCN) to see if they are set up and maintained properly. So far, Watts and his volunteers have checked about 820 of the weather stations, which have been in place for about 100 years and are the source for the country's official average annual temperature. Watts has found that temperature data from nearly 70 percent of the stations is of questionable accuracy because the stations do not adhere to the USHCN's own quality-control guidelines. I talked to Watts April 16 by phone from his office in Chico, Calif.
Q: Why do you do your blog WattsUpWithThat?
A: Well, it's just an extension of what my life has been up until the last few years. I was a broadcaster on television - a meteorologist - for 25 years. I look at the blog as really no different. I did a daily broadcast each day in television. A blog is really just a daily broadcast in a different form.
Q: Who is your target audience?
A: I never really thought about a target audience. I took the same philosophy from broadcasting. I made it to reach as broad an audience as possible and the demographics that I get from it tell me I am doing that job successfully. I've got everything from people with high school educations to people that are Ph.Ds who are reading and commentating and sometimes even submitting articles.
Q: Sometimes it gets pretty deep - lots of scientific charts and data.
A: It does. But that is to be expected because of the broad audience we have. My job is to try to make everything understandable, even for people who are not in tune with some of the more technical details of climate.
Q: Have you become more politicized since you began blogging? Or are you primarily still a man of science?
A: Well, my main interest always has been the science. I am still of the belief that you should let the data tell you what the real story is. As far as the blog goes, the only thing I can say that I've become a little more critical of in terms of politics is that we have some people now who should be sticking to science, such as Jim Hansen (head of NASA's Goddard Institute for Space Studies, going out and advocating things such as civil disobedience (at coal-fired power plants). That concerns me.
Q: What is your basic position on the question of global warming? Are you a believer? A skeptic? Somewhere in between?
A: I would call myself what some people describe as a "lukewarmer" in that the CO2 effect that people have done thousands of studies on is in fact real. However, it is not a crisis. The reason it is not a crisis is because most people do not understand the logarithmic nature of the CO2 response in our atmosphere.
Q: And that means?
A: It's like salting soup. If you have a bowl of soup in front of you and you put a little salt in it to salt it to taste, you say, "Well, maybe it needs just a tad more." So you add some more salt and you think, "Maybe not quite enough." Then you add some more, and all the sudden it's too salty. Now if you were to add additional salt to the soup, you could not determine that it was any more salty than it already was. And if you continue to add salt, you can't tell the difference.
CO2 is much like that in the way that our atmosphere responds to long-wave outgoing radiation, or trapping of heat. At some point when you get to a certain level, like a doubling of CO2, and then you add a second doubling of CO2, the response halves. It's logarithmic. Then it halves again and then halves again after that. So much of the effect that we would expect to see from CO2 -- because of this logarithmic response -- has already happened. In essence, our soup is already fairly well salted and additional salting is not to make a whole lot of difference.
Q: What is the most harmful "fact" - quote unquote - about global warming that everyone believes but which is probably not true or at least uncertain?
A: There is a belief out there that we will get into a runaway condition where at some point a tipping point would occur and that at that point there is no turning back and then the world would destroy itself. That is being pushed in the media a lot and it is flat wrong.
As we go back into history, into past millennia, we can see that our atmosphere has in fact had much more CO2 - up to 6,000 parts per million, compared to the 380 parts per million that we have now - and it has responded and it has settled. Earth didn't destroy itself. It didn't burn up and boil off the oceans. So the comparison that we see with runaway global warming and the turning of Earth into Venus, things of that nature, are probably the most dangerous and wrong ideas that are being pushed.
Q: Are your troubled or annoyed by the way global warming is being discussed or covered by the mainstream media?
A: I am. And mainly because it's getting a free pass for almost every problem that's brought up. There's a Web site in the UK called Number Watch (numberwatch.com) that maintains a list of literally thousands of things in the media that are blamed on global warming. It's almost like "The Devil made me do it." The idea here is that, yeah, we have an issue and the issue is that there is some warming of the atmosphere.. That warming however is not catastrophic. It has occurred in the past and the Earth has survived. So the blaming of global warming as a catchall for every problem that we see in our environment is a disservice to science and to the people.
Q: My grandchildren ask me if the polar ice in the Northern Hemisphere is going to disappear?
A: I would say that the polar ice has disappeared in the past. Certainly there seems to be evidence of past climate situations where we may have had virtually no or none during the summertime. In the immediate future, however, I don't think we are going to see that. In fact, we're going through a rebound right now. If you look at the current Arctic ice extent from the Japanese agency which tracks the Arctic ice, you'll find that it is very near normal at this point and it is rebounding well from the last couple years. Antarctic ice is above normal. And the global total amount of sea ice is above normal. So it's not disappearing any time soon.
Q: What's the story with the Sun? It's been described as being asleep or in a state of "slumber" because it has had virtually no sun spots for a long time. What's going on?
A: Well, the Sun is driven by dynamic magnetic cycles. There are 11-year and 22-year cycles that have been identified and there are longer cycles that have been theorized. In every kind of a cycling endeavor there are always lulls and there are giant peaks. We've seen both in the past. We've seen lulls in the Maunder Minimum (1645 to 1715) and the Dalton Minimum (1790 to 1830), when virtually no sun spots appeared. Coincidentally, during those periods the weather and climate on Earth got colder.
The period that we are currently in now is what appears to be the beginning of an extended solar cycle that may now be as long as 12 1/2 years, compared to the normal 11. The current state of the Sun appears to be a similar kind of situation being set up to what it was right before the Dalton Minimum. So the possibility exists that we may find ourselves in a period of cooler weather in the next 20 to 30 years.
The missing link, however, between solar activity and Earth's climate is "What is the amplification factor?" The total solar irradiance, or TSI, has shown to be very small and when you look at the amount of watts per meter that is delivered to the Earth's surface, the amount of change in total solar irradiance doesn't appear to be enough to cause such differences in the climate of the Earth.
However, what people are looking for now is an amplification factor - sort of a climatic transistor, if you will. A transistor takes very small signals and amplifies them so they are audible - which is why radios work. The theory has been bandied about that the same kind of process occurs in Earth's climate. A very small change in signal related to solar activity - and we don't know which signal yet; it could be total solar irradiance, it could be ultraviolent; it could be magnetic; it could be cosmic rays; there are number of things that are being looked at -- gets amplified in Earth's natural processes and changes. That's what needs to be identified before a complete causal relationship is established between changes on the Sun's solar cycle and changes in Earth's climate.
Q: When we know the immense size of the Sun and power of the Sun and relative tininess of Earth, doesn't the Sun just scream out as being the chief culprit of climate change on Earth?
A: On the surface -- on a simple analysis -- one would think that. But again, the missing link is, what is the true causal relationship between changes in the Sun's solar cycle and Earth climate. Where's the amplification factor? Because just the change in the amount of sunlight that occurs doesn't appear to be enough to account for the observed changes in the past. So we are looking for that link.
However, I would say that the Sun really is the Big Kahuna of all the climate on earth. We would not have any climate. We would not have any weather. We would not have any ocean currents. We would not have life. We would have nothing if it were not for the Sun. So the Sun is this central point from which everything on Earth springs. We should not ignore that fact.
Q: Is a period of global cooling coming? And if so, what would you point to as evidence of that?
A: Well, there is a post on my blog today (April 16) about the computer models (of future global average temperatures) starting to diverge from the climate reality. This is something that is really kind of unexpected. The models continue to go up in (global temperature) but the climate reality and the current (global temperature) measurement starts to go down. They are diverging and have been diverging since 2006. There are a number of things that have aligned that make me think that perhaps we are in for a cooling period. The Pacific Decadal Oscillation, for example, has shifted from its warm regime to its cold regime last year. NASA JPL certified this. The last time it switched -- in 1978 -- it switched from a cool regime to a warm regime. We've been riding that warm period all the way since then.
Q: Is there a quick way to explain what the Pacific Decadal Oscillation is?
A: It has a larger influence that either El Nina or El Nino. It is a broad swath of water that extends from the Equator up into Alaska that changes the character of the surface temperatures of the Pacific over that broad swath of water. It was discovered by looking into changes in fishery stock by the University of Washington. The fishing stocks were changing and they had no explanation for it. They starting looking for it and they discovered it was linked to the food supply. And the food supply - krill and phytoplankton and all that sort of stuff - was linked to the changes in the temperature of the water. So they discovered this pattern. So it's a broad, wholesale change in the structure of the surface temperature of the Pacific.
Q: That has obvious influences over the whole climate for years afterwards.
A: Particularly the United States, because the weather flows from west to east. And particularly California. California had a fairly cool climate prior to 1978. And during the warmer period from 1978 to last year, agriculture boomed in California. Grapes began to be grown in places they haven't been grown before. The wine industry expanded. Agricultural expanded. And it expanded under a warmer climatic regime. Now that warmer climatic regime is in danger of shrinking again. So we may find growing seasons and growing places reduced back to areas that they were historically at in 1978.
Q: What is the most important, irrefutable truth about the climate of Earth that you wish every schoolchild and every elected official in Washington understood?
A: That the climate has always changed. It has never been static. In the past it has seen extremes hotter and colder than what we experience today. So change is normal.
Q: Since you are a meteorologist, I'll put you on the spot. Ten years from now what will we be talking about, global warming or global cooling?
A: I believe it will be global cooling, based on the fact that there are several things aligning - like the Pacific Decadal Oscillation and the solar patterns and so forth -- to make it appear that we might be in for a period of global cooling. However, I am also prepared to say that I may be completely wrong.
Copyright © 2009 Salem Web Network. All Rights Reserved.
Talking Climate Change with Anthony Watts
Bill Steigerwald
Monday, April 20, 2009
Anyone who regularly tunes into WattsUpWithThat.com, the popular climate-science blog operated by Anthony Watts, will never make fun of TV weathermen again. Watts - who was a TV meteorologist for 25 years - provides a steady diet of smart, always interesting and sometimes deeply complex scientific information and opinion about global climate change. Watts is also the founder of surfacestations.org, a project that for nearly two years has been quality-checking each of the 1,200-plus weather stations of the U. S. Historical Climate Network (USHCN) to see if they are set up and maintained properly. So far, Watts and his volunteers have checked about 820 of the weather stations, which have been in place for about 100 years and are the source for the country's official average annual temperature. Watts has found that temperature data from nearly 70 percent of the stations is of questionable accuracy because the stations do not adhere to the USHCN's own quality-control guidelines. I talked to Watts April 16 by phone from his office in Chico, Calif.
Q: Why do you do your blog WattsUpWithThat?
A: Well, it's just an extension of what my life has been up until the last few years. I was a broadcaster on television - a meteorologist - for 25 years. I look at the blog as really no different. I did a daily broadcast each day in television. A blog is really just a daily broadcast in a different form.
Q: Who is your target audience?
A: I never really thought about a target audience. I took the same philosophy from broadcasting. I made it to reach as broad an audience as possible and the demographics that I get from it tell me I am doing that job successfully. I've got everything from people with high school educations to people that are Ph.Ds who are reading and commentating and sometimes even submitting articles.
Q: Sometimes it gets pretty deep - lots of scientific charts and data.
A: It does. But that is to be expected because of the broad audience we have. My job is to try to make everything understandable, even for people who are not in tune with some of the more technical details of climate.
Q: Have you become more politicized since you began blogging? Or are you primarily still a man of science?
A: Well, my main interest always has been the science. I am still of the belief that you should let the data tell you what the real story is. As far as the blog goes, the only thing I can say that I've become a little more critical of in terms of politics is that we have some people now who should be sticking to science, such as Jim Hansen (head of NASA's Goddard Institute for Space Studies, going out and advocating things such as civil disobedience (at coal-fired power plants). That concerns me.
Q: What is your basic position on the question of global warming? Are you a believer? A skeptic? Somewhere in between?
A: I would call myself what some people describe as a "lukewarmer" in that the CO2 effect that people have done thousands of studies on is in fact real. However, it is not a crisis. The reason it is not a crisis is because most people do not understand the logarithmic nature of the CO2 response in our atmosphere.
Q: And that means?
A: It's like salting soup. If you have a bowl of soup in front of you and you put a little salt in it to salt it to taste, you say, "Well, maybe it needs just a tad more." So you add some more salt and you think, "Maybe not quite enough." Then you add some more, and all the sudden it's too salty. Now if you were to add additional salt to the soup, you could not determine that it was any more salty than it already was. And if you continue to add salt, you can't tell the difference.
CO2 is much like that in the way that our atmosphere responds to long-wave outgoing radiation, or trapping of heat. At some point when you get to a certain level, like a doubling of CO2, and then you add a second doubling of CO2, the response halves. It's logarithmic. Then it halves again and then halves again after that. So much of the effect that we would expect to see from CO2 -- because of this logarithmic response -- has already happened. In essence, our soup is already fairly well salted and additional salting is not to make a whole lot of difference.
Q: What is the most harmful "fact" - quote unquote - about global warming that everyone believes but which is probably not true or at least uncertain?
A: There is a belief out there that we will get into a runaway condition where at some point a tipping point would occur and that at that point there is no turning back and then the world would destroy itself. That is being pushed in the media a lot and it is flat wrong.
As we go back into history, into past millennia, we can see that our atmosphere has in fact had much more CO2 - up to 6,000 parts per million, compared to the 380 parts per million that we have now - and it has responded and it has settled. Earth didn't destroy itself. It didn't burn up and boil off the oceans. So the comparison that we see with runaway global warming and the turning of Earth into Venus, things of that nature, are probably the most dangerous and wrong ideas that are being pushed.
Q: Are your troubled or annoyed by the way global warming is being discussed or covered by the mainstream media?
A: I am. And mainly because it's getting a free pass for almost every problem that's brought up. There's a Web site in the UK called Number Watch (numberwatch.com) that maintains a list of literally thousands of things in the media that are blamed on global warming. It's almost like "The Devil made me do it." The idea here is that, yeah, we have an issue and the issue is that there is some warming of the atmosphere.. That warming however is not catastrophic. It has occurred in the past and the Earth has survived. So the blaming of global warming as a catchall for every problem that we see in our environment is a disservice to science and to the people.
Q: My grandchildren ask me if the polar ice in the Northern Hemisphere is going to disappear?
A: I would say that the polar ice has disappeared in the past. Certainly there seems to be evidence of past climate situations where we may have had virtually no or none during the summertime. In the immediate future, however, I don't think we are going to see that. In fact, we're going through a rebound right now. If you look at the current Arctic ice extent from the Japanese agency which tracks the Arctic ice, you'll find that it is very near normal at this point and it is rebounding well from the last couple years. Antarctic ice is above normal. And the global total amount of sea ice is above normal. So it's not disappearing any time soon.
Q: What's the story with the Sun? It's been described as being asleep or in a state of "slumber" because it has had virtually no sun spots for a long time. What's going on?
A: Well, the Sun is driven by dynamic magnetic cycles. There are 11-year and 22-year cycles that have been identified and there are longer cycles that have been theorized. In every kind of a cycling endeavor there are always lulls and there are giant peaks. We've seen both in the past. We've seen lulls in the Maunder Minimum (1645 to 1715) and the Dalton Minimum (1790 to 1830), when virtually no sun spots appeared. Coincidentally, during those periods the weather and climate on Earth got colder.
The period that we are currently in now is what appears to be the beginning of an extended solar cycle that may now be as long as 12 1/2 years, compared to the normal 11. The current state of the Sun appears to be a similar kind of situation being set up to what it was right before the Dalton Minimum. So the possibility exists that we may find ourselves in a period of cooler weather in the next 20 to 30 years.
The missing link, however, between solar activity and Earth's climate is "What is the amplification factor?" The total solar irradiance, or TSI, has shown to be very small and when you look at the amount of watts per meter that is delivered to the Earth's surface, the amount of change in total solar irradiance doesn't appear to be enough to cause such differences in the climate of the Earth.
However, what people are looking for now is an amplification factor - sort of a climatic transistor, if you will. A transistor takes very small signals and amplifies them so they are audible - which is why radios work. The theory has been bandied about that the same kind of process occurs in Earth's climate. A very small change in signal related to solar activity - and we don't know which signal yet; it could be total solar irradiance, it could be ultraviolent; it could be magnetic; it could be cosmic rays; there are number of things that are being looked at -- gets amplified in Earth's natural processes and changes. That's what needs to be identified before a complete causal relationship is established between changes on the Sun's solar cycle and changes in Earth's climate.
Q: When we know the immense size of the Sun and power of the Sun and relative tininess of Earth, doesn't the Sun just scream out as being the chief culprit of climate change on Earth?
A: On the surface -- on a simple analysis -- one would think that. But again, the missing link is, what is the true causal relationship between changes in the Sun's solar cycle and Earth climate. Where's the amplification factor? Because just the change in the amount of sunlight that occurs doesn't appear to be enough to account for the observed changes in the past. So we are looking for that link.
However, I would say that the Sun really is the Big Kahuna of all the climate on earth. We would not have any climate. We would not have any weather. We would not have any ocean currents. We would not have life. We would have nothing if it were not for the Sun. So the Sun is this central point from which everything on Earth springs. We should not ignore that fact.
Q: Is a period of global cooling coming? And if so, what would you point to as evidence of that?
A: Well, there is a post on my blog today (April 16) about the computer models (of future global average temperatures) starting to diverge from the climate reality. This is something that is really kind of unexpected. The models continue to go up in (global temperature) but the climate reality and the current (global temperature) measurement starts to go down. They are diverging and have been diverging since 2006. There are a number of things that have aligned that make me think that perhaps we are in for a cooling period. The Pacific Decadal Oscillation, for example, has shifted from its warm regime to its cold regime last year. NASA JPL certified this. The last time it switched -- in 1978 -- it switched from a cool regime to a warm regime. We've been riding that warm period all the way since then.
Q: Is there a quick way to explain what the Pacific Decadal Oscillation is?
A: It has a larger influence that either El Nina or El Nino. It is a broad swath of water that extends from the Equator up into Alaska that changes the character of the surface temperatures of the Pacific over that broad swath of water. It was discovered by looking into changes in fishery stock by the University of Washington. The fishing stocks were changing and they had no explanation for it. They starting looking for it and they discovered it was linked to the food supply. And the food supply - krill and phytoplankton and all that sort of stuff - was linked to the changes in the temperature of the water. So they discovered this pattern. So it's a broad, wholesale change in the structure of the surface temperature of the Pacific.
Q: That has obvious influences over the whole climate for years afterwards.
A: Particularly the United States, because the weather flows from west to east. And particularly California. California had a fairly cool climate prior to 1978. And during the warmer period from 1978 to last year, agriculture boomed in California. Grapes began to be grown in places they haven't been grown before. The wine industry expanded. Agricultural expanded. And it expanded under a warmer climatic regime. Now that warmer climatic regime is in danger of shrinking again. So we may find growing seasons and growing places reduced back to areas that they were historically at in 1978.
Q: What is the most important, irrefutable truth about the climate of Earth that you wish every schoolchild and every elected official in Washington understood?
A: That the climate has always changed. It has never been static. In the past it has seen extremes hotter and colder than what we experience today. So change is normal.
Q: Since you are a meteorologist, I'll put you on the spot. Ten years from now what will we be talking about, global warming or global cooling?
A: I believe it will be global cooling, based on the fact that there are several things aligning - like the Pacific Decadal Oscillation and the solar patterns and so forth -- to make it appear that we might be in for a period of global cooling. However, I am also prepared to say that I may be completely wrong.
Copyright © 2009 Salem Web Network. All Rights Reserved.
Saturday, April 18, 2009
Antarctic ice is growing, not melting away
http://www.news.com.au/story/0,27574,25348657-401,00.html
By Greg Roberts
The Australian
April 18, 2009 11:52am
Antarctic / Reuters
Cool down ... ice is expanding in much of the Antarctic, experts say / Reuters
* Ice expanding in much of Antarctica
* Eastern coast getting colder
* Western section remains a concern
ICE is expanding in much of Antarctica, contrary to the widespread public belief that global warming is melting the continental ice cap.
The results of ice-core drilling and sea ice monitoring indicate there is no large-scale melting of ice over most of Antarctica, although experts are concerned at ice losses on the continent's western coast.
Antarctica has 90 per cent of the Earth's ice and 80 per cent of its fresh water, The Australian reports. Extensive melting of Antarctic ice sheets would be required to raise sea levels substantially, and ice is melting in parts of west Antarctica. The destabilisation of the Wilkins ice shelf generated international headlines this month.
However, the picture is very different in east Antarctica, which includes the territory claimed by Australia.
East Antarctica is four times the size of west Antarctica and parts of it are cooling. The Scientific Committee on Antarctic Research report prepared for last week's meeting of Antarctic Treaty nations in Washington noted the South Pole had shown "significant cooling in recent decades".
Australian Antarctic Division glaciology program head Ian Allison said sea ice losses in west Antarctica over the past 30 years had been more than offset by increases in the Ross Sea region, just one sector of east Antarctica.
"Sea ice conditions have remained stable in Antarctica generally," Dr Allison said.
The melting of sea ice - fast ice and pack ice - does not cause sea levels to rise because the ice is in the water. Sea levels may rise with losses from freshwater ice sheets on the polar caps. In Antarctica, these losses are in the form of icebergs calved from ice shelves formed by glacial movements on the mainland.
Last week, federal Environment Minister Peter Garrett said experts predicted sea level rises of up to 6m from Antarctic melting by 2100, but the worst case scenario foreshadowed by the SCAR report was a 1.25m rise.
Mr Garrett insisted global warming was causing ice losses throughout Antarctica. "I don't think there's any doubt it is contributing to what we've seen both on the Wilkins shelf and more generally in Antarctica," he said.
Dr Allison said there was not any evidence of significant change in the mass of ice shelves in east Antarctica nor any indication that its ice cap was melting. "The only significant calvings in Antarctica have been in the west," he said. And he cautioned that calvings of the magnitude seen recently in west Antarctica might not be unusual.
"Ice shelves in general have episodic carvings and there can be large icebergs breaking off - I'm talking 100km or 200km long - every 10 or 20 or 50 years."
Ice core drilling in the fast ice off Australia's Davis Station in East Antarctica by the Antarctic Climate and Ecosystems Co-Operative Research Centre shows that last year, the ice had a maximum thickness of 1.89m, its densest in 10 years. The average thickness of the ice at Davis since the 1950s is 1.67m.
A paper to be published soon by the British Antarctic Survey in the journal Geophysical Research Letters is expected to confirm that over the past 30 years, the area of sea ice around the continent has expanded.
By Greg Roberts
The Australian
April 18, 2009 11:52am
Antarctic / Reuters
Cool down ... ice is expanding in much of the Antarctic, experts say / Reuters
* Ice expanding in much of Antarctica
* Eastern coast getting colder
* Western section remains a concern
ICE is expanding in much of Antarctica, contrary to the widespread public belief that global warming is melting the continental ice cap.
The results of ice-core drilling and sea ice monitoring indicate there is no large-scale melting of ice over most of Antarctica, although experts are concerned at ice losses on the continent's western coast.
Antarctica has 90 per cent of the Earth's ice and 80 per cent of its fresh water, The Australian reports. Extensive melting of Antarctic ice sheets would be required to raise sea levels substantially, and ice is melting in parts of west Antarctica. The destabilisation of the Wilkins ice shelf generated international headlines this month.
However, the picture is very different in east Antarctica, which includes the territory claimed by Australia.
East Antarctica is four times the size of west Antarctica and parts of it are cooling. The Scientific Committee on Antarctic Research report prepared for last week's meeting of Antarctic Treaty nations in Washington noted the South Pole had shown "significant cooling in recent decades".
Australian Antarctic Division glaciology program head Ian Allison said sea ice losses in west Antarctica over the past 30 years had been more than offset by increases in the Ross Sea region, just one sector of east Antarctica.
"Sea ice conditions have remained stable in Antarctica generally," Dr Allison said.
The melting of sea ice - fast ice and pack ice - does not cause sea levels to rise because the ice is in the water. Sea levels may rise with losses from freshwater ice sheets on the polar caps. In Antarctica, these losses are in the form of icebergs calved from ice shelves formed by glacial movements on the mainland.
Last week, federal Environment Minister Peter Garrett said experts predicted sea level rises of up to 6m from Antarctic melting by 2100, but the worst case scenario foreshadowed by the SCAR report was a 1.25m rise.
Mr Garrett insisted global warming was causing ice losses throughout Antarctica. "I don't think there's any doubt it is contributing to what we've seen both on the Wilkins shelf and more generally in Antarctica," he said.
Dr Allison said there was not any evidence of significant change in the mass of ice shelves in east Antarctica nor any indication that its ice cap was melting. "The only significant calvings in Antarctica have been in the west," he said. And he cautioned that calvings of the magnitude seen recently in west Antarctica might not be unusual.
"Ice shelves in general have episodic carvings and there can be large icebergs breaking off - I'm talking 100km or 200km long - every 10 or 20 or 50 years."
Ice core drilling in the fast ice off Australia's Davis Station in East Antarctica by the Antarctic Climate and Ecosystems Co-Operative Research Centre shows that last year, the ice had a maximum thickness of 1.89m, its densest in 10 years. The average thickness of the ice at Davis since the 1950s is 1.67m.
A paper to be published soon by the British Antarctic Survey in the journal Geophysical Research Letters is expected to confirm that over the past 30 years, the area of sea ice around the continent has expanded.
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