Another new study indicates this.

http://www.usgs.gov/newsroom/article.asp?ID=2358

The climate may be 30–50 percent more sensitive to atmospheric carbon dioxide in the long term than previously thought, according to a study published in Nature Geoscience yesterday.

Projections over the next hundreds of years of climate conditions, including global temperatures, may need to be adjusted to reflect this higher sensitivity.

“Climate change is affecting water supplies for cities and farms; leading to more severe droughts, hurricanes, and floods; contributing to more intense forest fires; and putting coastal communities at risk,” said Secretary of the Interior Ken Salazar, who is on his way to the global climate change conference convening this week in Copenhagen. “This study and the ongoing work of our USGS scientists will help us continue to build more precise long-term projections and to prepare for the impacts of climate change on our world.”

A team of scientists, led by the University of Bristol and including the U.S. Geological Survey, studied global temperatures 3.3 to 3 million years ago, finding that the averages were significantly higher than expected from the atmospheric carbon dioxide levels at the time.

These underestimates occurred because the long-term sensitivity of the Earth system was not accurately taken into account. In these earlier periods, Earth had more time to adjust to some of the slower impacts of climate change. For example, as the climate warms and ice sheets melt, Earth will absorb more sunlight and continue to warm in the future since less ice is present to reflect the sun.

The U.S. Geological Survey provided the reconstruction of environmental conditions during this timeframe, known as the mid-Pliocene warm period. These data allowed the authors to test the Earth system’s sensitivity to atmospheric carbon dioxide.

“Earth is a dynamic system and climate models need to incorporate its multiple feedbacks as well as changes on both fast and long timescales,” said Dr. Dan Lunt, who is with the University of Bristol and was the lead author of this article. “This comprehensive outlook allows us to see how sensitive the climate really is to atmospheric carbon dioxide, resulting in more accurate long-term projections.”
Good answers by Icarus, Dana, and Keith. Much appreciated! This is the kind of intelligent discussion sorely lacking in the majority of questions in this category.

Myth #1: Scientists Agree the Earth Is Warming. While ground-level temperature measurements suggest the earth has warmed between 0.3 and 0.6 degrees Celsius since 1850, global satellite data, the most reliable of climate measurements, show no evidence of warming during the past 18 years. Even if the earth’s temperature has increased slightly, the increase is well within the natural range of known temperature variation over the last 15,000 years. Indeed, the earth experienced greater warming between the 10th and 15th centuries - a time when vineyards thrived in England and Vikings colonized Greenland and built settlements in Canada.

Myth #2: Humans Are Causing Global Warming. Scientists do not agree that humans discernibly influence global climate because the evidence supporting that theory is weak. The scientific experts most directly concerned with climate conditions reject the theory by a wide margin.

* A Gallup poll found that only 17 percent of the members of the Meteorological Society and the American Geophysical Society think that the warming of the 20th century has been a result of greenhouse gas emissions - principally CO2 from burning fossil fuels. [See Figure II.]
* Only 13 percent of the scientists responding to a survey conducted by the environmental organization Greenpeace believe catastrophic climate change will result from continuing current patterns of energy use.
* More than 100 noted scientists, including the former president of the National Academy of Sciences, signed a letter declaring that costly actions to reduce greenhouse gases are not justified by the best available evidence.

While atmospheric carbon dioxide has increased by 28 percent over the past 150 years, human-generated carbon dioxide could have played only a small part in any warming, since most of the warming occurred prior to 1940 - before most human-caused carbon dioxide emissions.

Myth # 3: Human-Caused Global Warming Will Cause Cataclysmic Environmental Problems.Sea levels are rising around the globe, though not uniformly. In fact, sea levels have risen more than 300 feet over the last 18,000 years - far predating any possible human impact. Rising sea levels are natural in between ice ages. Contrary to the predictions of global warming theorists, the current rate of increase is slower than the average rate over the 18,000-year period.
* Since the 1940s the National Oceanographic and Meteorological Laboratory has documented a decrease in both the intensity and number of hurricanes.
* From 1991 through 1995, relatively few hurricanes occurred, and even the unusually intense 1995 hurricane season did not reverse the downward trend.
* The 1996 IPCC report on climate change found a worldwide significant increase in tropical storms unlikely; some regions may experience increased activity while others will see fewer, less severe storms.

"If you tell a lie long enough and loud enough, people will start to believe it"- Hitler
Get a clue and don’t buy everything your political leaders want you to believe…they have other motives!
Oh poor Dawei, its hard to argue with the facts isn’t it, well a clever little snip will be just as efficient as a valid argument won’t it? Keep spending that extra money to live "Green" your paying Al Gore’s enormous power bill.