A statement from the American Geophysical Union

[mendeleev 68]

Human Impacts on Climate

The Earth's climate is now clearly out of balance and is warming. Many components of the climate system — including the temperatures of the atmosphere, land and ocean, the extent of sea ice and mountain glaciers, the sea level, the distribution of precipitation, and the length of seasons — are now changing at rates and in patterns that are not natural and are best explained by the increased atmospheric abundances of greenhouse gases and aerosols generated by human activity during the 20th century.

Global average surface temperatures increased on average by about 0.6 degrees Celsius over the period 1956-2006. As of 2006, eleven of the previous twelve years were warmer than any others since 1850. The observed rapid retreat of Arctic sea ice is expected to continue and lead to the disappearance of summertime ice within this century. Evidence from most oceans and all continents except Antarctica shows warming attributable to human activities. Recent changes in many physical and biological systems are linked with this regional climate change. A sustained research effort, involving many AGU members and summarized in the 2007 assessments of the Intergovernmental Panel on Climate Change, continues to improve our scientific understanding of the climate.

During recent millennia of relatively stable climate, civilization became established and populations have grown rapidly. In the next 50 years, even the lower limit of impending climate change — an additional global mean warming of 1 degree Celsius above the last decade — is far beyond the range of climate variability experienced during the past thousand years and poses global problems in planning for and adapting to it. Warming greater than 2 degrees Celsius above 19th century levels is projected to be disruptive, reducing global agricultural productivity, causing widespread loss of biodiversity, and — if sustained over centuries — melting much of the Greenland ice sheet with ensuing rise in sea level of several meters. If this 2 degrees Celsius warming is to be avoided, then our net annual emissions of carbon dioxide must be reduced by more than 50 percent within this century. With such projections, there are many sources of scientific uncertainty, but none are known that could make the impact of climate change inconsequential. Given the uncertainty in climate projections, there can be surprises that may cause more dramatic disruptions than anticipated from the most probable model projections.

With climate change, as with ozone depletion, the human footprint on Earth is apparent. The cause of disruptive climate change, unlike ozone depletion, is tied to energy use and runs through modern society. Solutions will necessarily involve all aspects of society. Mitigation strategies and adaptation responses will call for collaborations across science, technology, industry, and government. Members of the AGU, as part of the scientific community, collectively have special responsibilities: to pursue research needed to understand it; to educate the public on the causes, risks, and hazards; and to communicate clearly and objectively with those who can implement policies to shape future climate.

Adopted by AGU Council, December, 2003

Revised and Reaffirmed, December, 2007

[luv2uallday 1]

Human Impacts on Climate

The Earth's climate is now clearly out of balance and is warming. Many components of the climate system — including the temperatures of the atmosphere, land and ocean, the extent of sea ice and mountain glaciers, the sea level, the distribution of precipitation, and the length of seasons — are now changing at rates and in patterns that are not natural and are best explained by the increased atmospheric abundances of greenhouse gases and aerosols generated by human activity during the 20th century.

Global average surface temperatures increased on average by about 0.6 degrees Celsius over the period 1956-2006. As of 2006, eleven of the previous twelve years were warmer than any others since 1850. The observed rapid retreat of Arctic sea ice is expected to continue and lead to the disappearance of summertime ice within this century. Evidence from most oceans and all continents except Antarctica shows warming attributable to human activities. Recent changes in many physical and biological systems are linked with this regional climate change. A sustained research effort, involving many AGU members and summarized in the 2007 assessments of the Intergovernmental Panel on Climate Change, continues to improve our scientific understanding of the climate.

During recent millennia of relatively stable climate, civilization became established and populations have grown rapidly. In the next 50 years, even the lower limit of impending climate change — an additional global mean warming of 1 degree Celsius above the last decade — is far beyond the range of climate variability experienced during the past thousand years and poses global problems in planning for and adapting to it. Warming greater than 2 degrees Celsius above 19th century levels is projected to be disruptive, reducing global agricultural productivity, causing widespread loss of biodiversity, and — if sustained over centuries — melting much of the Greenland ice sheet with ensuing rise in sea level of several meters. If this 2 degrees Celsius warming is to be avoided, then our net annual emissions of carbon dioxide must be reduced by more than 50 percent within this century. With such projections, there are many sources of scientific uncertainty, but none are known that could make the impact of climate change inconsequential. Given the uncertainty in climate projections, there can be surprises that may cause more dramatic disruptions than anticipated from the most probable model projections.

With climate change, as with ozone depletion, the human footprint on Earth is apparent. The cause of disruptive climate change, unlike ozone depletion, is tied to energy use and runs through modern society. Solutions will necessarily involve all aspects of society. Mitigation strategies and adaptation responses will call for collaborations across science, technology, industry, and government. Members of the AGU, as part of the scientific community, collectively have special responsibilities: to pursue research needed to understand it; to educate the public on the causes, risks, and hazards; and to communicate clearly and objectively with those who can implement policies to shape future climate.

Adopted by AGU Council, December, 2003

Revised and Reaffirmed, December, 2007

ok first of all what does this have to do with immigration? I think you got lost somewhere.. Also, this planet is warming no doubt. The science behind this bull is not perfect and filled with politics.. But also more importantly the sun has increased its energy output and as a result all the other planets are warming as well.... so that proves one important point if the sun gets hotter the world gets hotter WOW what a surprise!!! go back to science class... We humans are soooo arogant to think we can single handedly destroy life on earth when the earth has seen pollution levels in its history that makes our pollution levels seem like nothing at all. It survived those times many times over what makes you think we are soo powerful to out do that? yes we can use up our water pollute our immediate surroundings, but change the whole global system? that is arrogance not intelligence...

[Peikko 1,575]

Whether or not there is man made global warming, the 'arrogance' argument is one of the more stupid ones.

Can humans materially effect life on earth? You bet they can. Humans can produce nuclear bombs. If enough of them were set off at one time I think it's safe to say that humans could effectively destroy life on earth.

However, that's not as likely to happen as say - deforestation. Is anyone seriously suggesting that the almost complete destruction of the South American rain forests would not have a profound affect on the biology of the planet? I think not. Again, what about the increase in acid in the oceans? Another man made problem that is devestating fragile ecosystems and the projected impact is colossal not just some local difficulty. Over fishing in the Mediteranean has already led to the depletion of fish stocks to catastrophic levels. Finally, population. Is it arrogant to suppose that increasing numbers of people on the planet are going to have an increasingly dramatic effect on the environment?

There is nothing 'arrogant' about the claim that man can and does affect the planet on a global scale. It is incredibly sad though that governments can't get their act together globaly to decide what to do about it in a way that would ensure that despite huge increases in population there will be a sustainable way to inhabit planet Earth for many millions of years to come.

Oh and, this is off topic which means, well, off topic subjects are pefectly welcome.

Edited January 26, 2008 by Purple_Hibiscus

[Hilarious Clinton 452]

ok first of all what does this have to do with immigration? I think you got lost somewhere.. Also, this planet is warming no doubt. The science behind this bull is not perfect and filled with politics.. But also more importantly the sun has increased its energy output and as a result all the other planets are warming as well.... so that proves one important point if the sun gets hotter the world gets hotter WOW what a surprise!!! go back to science class... We humans are soooo arogant to think we can single handedly destroy life on earth when the earth has seen pollution levels in its history that makes our pollution levels seem like nothing at all. It survived those times many times over what makes you think we are soo powerful to out do that? yes we can use up our water pollute our immediate surroundings, but change the whole global system? that is arrogance not intelligence...

This is off-topic. Get the memo?

I agree with the rest of your statement though.

[peejay 327]

There is ample history of man's greed, hubris, and arrogance in destroying our planet earth. Unfortunately the story isn't over yet.

The destruction of the Aral Sea in Central Asia and the American Dust Bowl are prime examples of large scale man made environmental disasters.

A recently published book on the Dust Bowl is an interesting and enlightening read:

The Worst Hard Time: The Untold Story of Those Who Survived the Great American Dust Bowl by Timothy Egan.

http://www.houghtonmifflinbooks.com/catalo...leNumber=688507

[Trumplestiltskin 5,791]

There is ample history of man's greed, hubris, and arrogance in destroying our planet earth. Unfortunately the story isn't over yet.

The destruction of the Aral Sea in Central Asia and the American Dust Bowl are prime examples of large scale man made environmental disasters.

A recently published book on the Dust Bowl is an interesting and enlightening read:

The Worst Hard Time: The Untold Story of Those Who Survived the Great American Dust Bowl by Timothy Egan.

http://www.houghtonmifflinbooks.com/catalo...leNumber=688507

Yeah I've read about that - intensive farming techniques during a drought season essentially pushed over the balance of nature and caused wholesale desertification.

Also human activity has been proven to cause and accelerate coastal erosion - usually by attempts to preserve beaches in resort towns..

Overgrazing and to a lesser extent drought in the 1930s transformed parts of the Great Plains in the United States into the "Dust Bowl". During that time, a considerable fraction of the plains population abandoned their homes to escape the unproductive lands. Improved agricultural and water management have prevented a disaster of the earlier magnitude from recurring, but desertification presently affects tens of millions of people with primary occurrence in the lesser developed countries.

Lake Chad in a 2001 satellite image, with the actual lake in blue. The lake has shrunk by 95% since the 1960's.[2]Desertification is widespread in many areas of the People's Republic of China. The populations of rural areas have increased since 1949 for political reasons as more people have settled there. While there has been an increase in livestock, the land available for grazing has decreased. Also the importing of European cattle such as Friesian and Simmental, which have higher food intakes, has made things worse.

Human overpopulation is leading to destruction of tropical wet forests and tropical dry forests, due to widening practices of slash-and-burn and other methods of subsistence farming necessitated by famines in lesser developed countries. A sequel to the deforestation is typically large scale erosion, loss of soil nutrients and sometimes total desertification. Examples of this extreme outcome can be seen on Madagascar's central highland plateau, where about seven percent of the country's total land mass has become barren, sterile land.

Overgrazing has made the Rio Puerco Basin of central New Mexico one of the most eroded river basins of the western United States and has increased the high sediment content of the river.[3] Overgrazing is also an issue with some regions of South Africa such as the Waterberg Massif, although restoration of native habitat and game has been pursued vigorously since about 1980.

Another example of desertification occurring is in the Sahel. The chief cause of desertification in the Sahel is slash-and-burn farming practised by an expanding human population.[4]

The Desert of Maine is a 40 acre dune of glacial silt near Freeport, Maine. Overgrazing and soil erosion exposed the cap of the dune, revealing the desert as a small patch that continued to grow, overtaking the land. The site is maintained as a tourist attraction.[5]

Ghana[6] and Nigeria currently experience desertification; in the latter, desertification overtakes about 1,355 square miles (3,510 km²) of land per year. The Central Asian countries, Afghanistan, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan, are also affected. More than 80% of Afghanistan's land could be subject to soil erosion and desertification.[7] In Kazakhstan, nearly half of the cropland has been abandoned since 1980. In Iran, sand storms were said to have buried 124 villages in Sistan and Baluchestan Province in 2002, and they had to be abandoned. In Latin America, Mexico and Brazil are affected by desertification.[8]

Global warming is leading to increased desertification in many areas of the world.

http://en.wikipedia.org/wiki/Desertificati...desertification

[Kazan' Tiger 1]

:lol:

This is off-topic. Get the memo?

[HAL 9000 96]

Hey novotul good to read you here again.

I guess the point of you being a scientist won't sway those that side with the flat earthists... :idea:

[one...two...tree 2,762]

Hey novotul good to read you here again.

I guess the point of you being a scientist won't sway those that side with the flat earthists... :idea:

I second that.

[kerewin21 2]

I still say all this global warming ####### is just a ploy by the evil scientists to get us to stop enjoying our rampant consumption of non-renewable resources. If I want a Hummer, I'll get a Hummer! And gas should only be $1 a gallon. The government should get right on that.

[GaryC 7]

Hey novotul good to read you here again.

I guess the point of you being a scientist won't sway those that side with the flat earthists... :idea:

Those that believe that man is causing global warming ARE the new flat earthists. They believe in unsubstantiated junk science. For them its belief rather than facts.

[Trumplestiltskin 5,791]

Hey novotul good to read you here again.

I guess the point of you being a scientist won't sway those that side with the flat earthists... :idea:

Those that believe that man is causing global warming ARE the new flat earthists. They believe in unsubstantiated junk science. For them its belief rather than facts.

There seems to be an awful lot of scientists who believe in the work they are doing - not to mention the fact that every major scientific professional association (bar one - but even they have started to publicly revise their position) agrees with the idea of human climate change.

[kerewin21 2]

Hey novotul good to read you here again.

I guess the point of you being a scientist won't sway those that side with the flat earthists... :idea:

Those that believe that man is causing global warming ARE the new flat earthists. They believe in unsubstantiated junk science. For them its belief rather than facts.

If every major scientific association in the country and world believe in "unsubstantiated junk science," who pray tell are the real scientists?

[Trumplestiltskin 5,791]

Hey novotul good to read you here again.

I guess the point of you being a scientist won't sway those that side with the flat earthists... :idea:

Those that believe that man is causing global warming ARE the new flat earthists. They believe in unsubstantiated junk science. For them its belief rather than facts.

If every major scientific association in the country and world believe in "unsubstantiated junk science," who pray tell are the real scientists?

Its a conspiracy is what it is

[one...two...tree 2,762]

Hey novotul good to read you here again.

I guess the point of you being a scientist won't sway those that side with the flat earthists... :idea:

Those that believe that man is causing global warming ARE the new flat earthists. They believe in unsubstantiated junk science. For them its belief rather than facts.

If every major scientific association in the country and world believe in "unsubstantiated junk science," who pray tell are the real scientists?

Exxon/Mobil contracted scientists.