WHAT A DIFFERENCE six years makes. Since the 2001 IPCC report, glaciers have rapidly retreated and scientists have become more certain that climate change is here to stay.
Image: © MOMATIUK-EASTCOTT/CORBIS
PARIS -- Six years is not a long time in science. Data may be collected, a paper or two published or a PhD earned. But in the six years since the last Intergovernmental Panel on Climate Charge (IPCC) report was released, the science and certainty of global warming has grown markedly. "In the first IPCC report in 1990 there were no real observations demonstrating that climate had changed, only a prognosis that it would change," says Herve Le Treut, atmospheric physicist at CNRS (France's National Center for Scientific Research) and a lead author of part of the fourth IPCC report set to be released on Friday. "By 2001, there were many signs that climate is changing and now we are already seeing the patterns described in the first IPCC report."
Simple observation confirms the basic science of climate change. "All six years since the last report (2001 to 2006) are among the seven warmest years on record," notes Kevin Trenberth, head of the Climate Analysis Section at the U.S. National Center for Atmospheric Research (NCAR) and another lead author. "Northern Hemisphere snow cover has decreased and Arctic Sea ice has been at record low levels in the past three years."
In addition to such ice changes--accelerated melting in Greenland, western Antarctica and from mountain glaciers throughout the world--scientists have improved their understanding of the atmosphere's workings. For example, the tiny particles known as aerosols are far better understood, says atmospheric scientist Piers Forster of the University of Leeds in England andalso a lead author. "We estimate that their total radiative forcing is around -1.3 [watts/meter2]," which is a cooling effect, he says. "Because of this and a better understanding of how forcing terms add up, we are able to sum the radiative forcings and, for the first time, come up with the statement that we have very high confidence that humans have had a warming influence since preindustrial times." That influence continues via greenhouse gases from burning fossil fuels, and other sources; the temperature forcing from carbon dioxide levels has jumped 20 percent in just the last 10 years.
These observational improvements also extend into space, all the way to the sun, where scientists have used satellite data to better understand the amount of solar energy--and its impact here on Earth. "We therefore can make a comparison statement for the first time and say it is likely that solar forcing is at least five times smaller than the combined human influence," Forster continues. "Over the last 50 years, in particular, the natural forcing (solar plus volcanic) is most certainly negative. Meanwhile we've seen this large positive forcing from greenhouse gases."
"There are now three or four satellite temperature time series of the atmosphere, six years ago there was one. This duplication helped uncover some errors," adds lead author Thomas Peterson, a climate analyst with the U.S. National Ocean and Atmospheric Administration (NOAA). "Correction of that error made the time series show more warming and is part of the reason why you no longer hear skeptics say that satellites don't show any warming."
In addition, tide gauges, satellite measurements and some 1,250 data-collecting buoys have improved information on oceans, the most important heat sink on Earth. "The oceanographic community now has a system of vertical profiling floats distributed through most of the world oceans that tells us the vertical distributions of temperature and salinity every 10 days to depths of one to two kilometers," says Sydney Levitus, director of NOAA's World Data Center for Oceanography and another lead author. "Sea level observations are telling us that during the past 100 years sea level has risen at an average rate of 1.7 millimeters per year," most of that due to thermal expansion as the top 700 meters of the oceans warms and expands. In fact, a paper in today's Science reveals that the 2001 IPCC report underestimated sea level rise as well as the average surface temperature--land and sea combined--for the globe.
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15 Comments
Add CommentThe cost of bailing out the US financial system is peanuts compared to the ammount of money that climate change will cost insurance companies over the next 50 years!
Reply | Report Abuse | Link to thisJust saying something, does not make it true. Repeating it over and over, will not increase it's validity. New data, coming in for 2008 and 2009, will be embarrassing for those who stick to dogma, and avoid reason. Cooling will create, real life, urgent, immediate problems. We will all be grateful, when warming trends return 10 or 15 years from now. In the meantime, lets all think warm thoughts, for one another.
Reply | Report Abuse | Link to thisFor deniers, no amount of scientific data will convince them to consider the evidence with an open mind. Their minds are closed. We have reached a point where we need to combat climate change and not waste time attempting to convince the unbelievers. That's the way it always is, particularly in an age were something called the Internet is filled with misinformation produced by those with money at stake.
Reply | Report Abuse | Link to thisRe: evenhanded
Reply | Report Abuse | Link to thisYour call for action, when it is obvious, that we don,t know what we are doing, is the classic definition of panic. In the movies, there is always someone around to give you a sharp slap. My question is... Who is close to you that can deliver the required treatment.
Karst,
Reply | Report Abuse | Link to thisTo answer your question....not you. But your method of argument is consistent with that of a classic denier. You state what the climate will do in the next 10 to 15 years...as if you had a crystal ball. That is not science; that is pure ego. There is no semblance of reason to be found in your comments...none. Science won't be denied...and goes on despite people like you.
I'm sorry, I couldn't resist. It was too funny.
Reply | Report Abuse | Link to this"In the first IPCC report in 1990 there were no real observations demonstrating that climate had changed..."
I look out my window every day and see that the climate has changed since the day before. It's weird how that works.
"...only a prognosis that it would change..."
Really? They predicted that the climate would change? How amazingly prescient!
"By 2001, there were many signs that climate is changing..."
No way!
We need to figure out how to get that darn climate to stop changing. It's wreaking all kinds of havoc: rain, snow, hurricanes, tornadoes, heat spells. Aaaarrgh! Stop the climate from changing! We need to move to a place that doesn't have a changing climate. Maybe the moon will do.
I do have to agree with laurenra7 that something is funny...really funny.
Reply | Report Abuse | Link to thisClimate: the average course or condition of the weather at a place usually over a period of years as exhibited by temperature, wind velocity, and precipitation
Weather: the state of the atmosphere with respect to heat or cold, wetness or dryness, calm or storm, clearness or cloudiness
Climate and weather are not equivalent terms. You can't look out your window and see that the climate has changed from the day before.
Sorry to inform you that the surface of the moon also varies in temperature depending on whether light from the sun is present at that particular location and time.
Sorry evenhanded. I'm funnier than you, but you make a good point about distinguishing between climate and weather.
Reply | Report Abuse | Link to thisNow, how do we get that darn climate to stop changing? It kinda sucked during the Ice Age and it seems a whole lot more livable now, but it keeps drifting one way or the other and refuses to stay put, even without humans worrying about it.
The moon is a lot more static. That might be a better place for the climate change worriers to live--or at least a lot less stressful.
Climates change...so who cares. Not laurenra7. My attitude is different. If we are the prime force behind the current climate change, then maybe we can do something about it. I will also note that the faster climates change, the more difficult it is for life to adapt to the change. That's true regardless of what force is behind the change. I guess I don't want to see human induced mass extinctions. But that's just me.
Reply | Report Abuse | Link to thisAs a former Republican that now an Independent, it seems that most of the disbelievers in global warming are those with either some financial stake in things staying as they are, or tend to vote Republican.
Reply | Report Abuse | Link to thisI doubt that most Republicans have never seen an environmental law that they really believed in.
I an a denier and I belive I have reason to be. I am 13 years old and whenever I look at global warming sights I can spot hole and mistakes in global warming theorys.
Reply | Report Abuse | Link to thisfor example
when people talk about greenhouse gasses they say that carbon dioxcide is the main greenhouse gas. well.. Its not. Carbon dioxcide is a secondary greenhouse gas and one of the least potent [ has the least effect on climate] water vapour is a primary greenhouse gas and its effects are great. For a example think of a cloudless morning. It is about 2 degrees c colder than a cloudy morning. yet water vapour is not mentioned on climate change sights.
Please do a report on the lack of sunspots on solar cycle 24. Explain to people what the consequenses of low sunspot activity meant to the climate on earth during the maunder and dalton minimums. Explain how starvation and disease were rampant when the sun went quiet. Why the lies? Why is the government afraid to tell us that billions are going to starve. You want science search Cycle 24.
Reply | Report Abuse | Link to thisGood news. Solar cycle 24 was expected in 2006. It got a very slow start in 2009. This appears to be the reason for this cold winter and the future cold winters until 2030. It appears that billions will starve and is probably why the smart guys got their money out of the market, even though you can't eat money. Historically periods with low sun spots were periods of bitter cold. Maunder minimum. Dalton minimum. Frozen Thames frozen Baltic, even frozen Nile in the ninth century. We will probably be thanking God people had those big Cadillacs in the sixties. The science of it is described by Theodor Landscheidt and Rhodes Fairbridge. see http://www.detectingdesign.com/ancientice.html
Reply | Report Abuse | Link to thisCARBON DIOXIDE IS NOT A POLLUTANT, it is an absolutely nesessary gas for the existence of life.
Reply | Report Abuse | Link to thisIT DOES NOT CAUSE GLOBAL WARMING, wake up people you are being lied to,conned. CO2 amount in the atmosphere follows temperature, it does not cause or lead temperature. Go look at the observed facts, don't let opinionators and theoryests think for you.
Cap and Trade is a huge TAX on poor people. Right now,as we speak, rich people are in Washington DC making up the rules to vastly enrich themselves.
As a scientist reading Scientific American I have never seen one good scientific evidence that CO2 causes global warming or that CO2 has any negative effects on the earth or life on the earth. We have had times in the past when the CO2 levels have been 12 times today's levels and yet the temperature dropped 15 degrees to an ice age while CO2 levels were increasing (450 million year ago). Near the end of the Jurassic period in earths history the CO2 levels were 3 times today's levels, they then doubled to over 6 times today's levels and during this doubling of the CO2 the temperature dropped 11 degrees. And in the past the most prolific time for plant and animal life was when CO2 levels were 5 to 10 times what we have today. http://www.geocraft.com/WVFossils/Carboniferous_climate.html
Reply | Report Abuse | Link to thisI do not want to hear that software projections show that CO2 causes warming, as a programmer I know the out come is no better than the input and today's programs cannot predict a month in advance let alone 50 years. Please provide me with real science, history or even a good set of facts. I have not seen one fact on CO2 caused warming yet your Scientific American continues to use the non scientific terms like, CO2 "may" destroy the earth, or CO2 "could" kill all life, or more CO2 "might" raise the sea level by 20 feet. All this sounds more like science fiction than science.