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.

I often have a difficult time figuring out the reason AGW deniers have such a difficult time understanding simple concepts because they intentionally misunderstand them, or because they’re just not too bright. A good example is "hide the decline", which most deniers were convinced referred to a supposed decline in global temperatures, even though the email in question was written right after the hottest year on record.

When they finally figured out the ‘decline’ referred to certain tree ring data, they then shifted their (intentional?) misunderstanding to the paleoclimate data.

The newest (intentional?) misunderstanding is the ‘missing energy’. It seems like a pretty simple concept to me - satellites measure a certain energy imbalance at the top of the atmosphere, but over the past 5 years, we haven’t been able to account for where about half of that energy has ended up. So there are a few possibilities. Maybe the satellite data is wrong, maybe the data or analysis of ocean temperatures is wrong, or maybe the energy is going somewhere that we’re not measuring, like oceans below 2000 km, for example.

But of course all deniers get from this is "alarmunists are wrong" and are "laughably stupid".
http://answers.yahoo.com/question/index;_ylt=AmN0nRHfABt_moF2SOSiZy_sy6IX;_ylv=3?qid=20100419114345AARuHFI&show=7#profile-info-t1zlbOURaa

Several denier answers start talking about climate models, even though these measurements have nothing to do with models. All immediately launch into attacks on ‘alarmunists’ without even bothering to try and understand the underlying discrepancy and its relation to AGW.

And it’s certainly not an isolated instance. Besides ‘hide the decline’ and ‘missing energy’ there’s also winter storms, hurricane frequency, the tropical troposphere ‘hot spot’, etc. Deniers consistently fail to understand basic climate science concepts.

The question is, do they fail to understand these concepts because they don’t want to understand them, or because they’re incapable of understanding them?
"I am convinced that you are not interested in the truth….[link to 'American Thinker' article]"

Yeah, I would call that intentional. Good example, jim.
pegminer - good example. I saw that Meadow question about 30% drop in ocean pH. That was a tough one for deniers, because they had to admit the ‘alarmist’ was right. Except bravo - the chemist who darn well should know the pH scale is logarithmic. Yet he just turned it into the usual ‘decreasing pH isn’t acidification’ semantics garbage. It was truly pathetic.

Both jimzulu brothers definitely fit the intentional category. They have the tools to understand these basic concepts, but are unwilling to bypass their political biases.

Both Northern Hemisphere and South Hemisphere AND therefore overall Global hurricane activity has continued to sink to levels not seen since the 1970s. Even more astounding, when the Southern Hemisphere hurricane data is analyzed to create a global value, we see that Global Hurricane Energy has sunk to 30-year lows, at the least.

http://wattsupwiththat.com/2009/09/22/global-warming-more-hurricanes-still-not-happening/
Dana:

Hurricane climate experts in your study depend on field data. The amount of hurricane data is not enough for your climate models to project real 20 to 100 year forecasts. Yet again they are estimations!

"Tropical cyclone (TC) activity worldwide has completely and utterly collapsed during the past 2 to 3 years with TC energy levels sinking to levels not seen since the late 1970s."

http://www.coaps.fsu.edu/~maue/tropical/

In 2005 we were told by the "experts" that Hurricane Katrina was a product of "Global Warming", that we should expect a greater number and greater strength of hurricanes in the future. The climate models backed up the claims of the scientists, and these statements were widely reported as facts about man’s effects on the climate.

Now the long term study is out that did study the number and strength of tropical storms and the facts are that both the number and intensity have decreased over the years since Katrina.

How did these climate models miss something as easy as this, and how were the top "Global Warming Experts" fooled by the data?

If something as simple as the number and strength of the storms are wrong, than can we accept that there is more data that is wrong that we don’t know about yet?

Should the data from "Global Warming" institutes be reviewed to separate what is opinion, emotion, political from true objective science?

There was a thread about the study earlier, but so much misinformation was being spread that I had to make some corrections.

Here is the link to the study: ftp://texmex.mit.edu/pub/emanuel/PAPERS/Emanuel_etal_2008.pdf

Now for the main conclusion:
"A new technique for deriving hurricane climatologies from global data, applied to climate
models, indicates that global warming should reduce the global frequency of hurricanes,
though their intensity may increase in some locations."

Says that there should be a reduction in overall frequency and intensity *may* increase in *some* places.

In the summary:
"This suggests either that the greater part of the large global increase in power dissipation over the past 27 yr cannot be ascribed to global warming, or that there is some systematic deficiency in our technique or in global models that leads to the under-prediction of the response of tropical cyclones to global warming."
That last quote essentially means that the increase in power dissipation over the last 30 years is not related to global warming or else current models are useless.

For the record, I think that this means that there is still much to learn–so many uncertainties. Current models don’t mean much in my book.
Tuba in the Rose said:
"This is a good example of a scientist finding a flaw in his earlier work and asking his peers to help him find and correct the error. It doesn’t prove or disprove anything.

If you want to track and critique his every word while he works on the problem, like paparazzi chasing Britany Spears, go ahead."

If all Emanuel wanted was help from his peers, it is not necessary to write that up in a study. This paper was an explanation of a new technique for predicting long term hurricane trends, and it is conflicting with earlier models (the new technique was meant to better match observations).

I never proposed that this work "proves" or "disproves" anything–I was merely pointing out his real conclusions, which aren’t that dramatic. Hardly sounds like "paparazzi." Your response to this thread seems odd, Tuba. Do you not wish to hear Emanuel’s conclusion?

As I pointed out above: this study means that there is still much work to be done.