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The past 30 years has seen more "hot" (orange), "very hot" (red) and "extremely hot" (brown) summers, compared to a base period defined in this study from 1951 to 1980  (Source: NASA/Goddard Space Flight Center Scientific Visualization Studio)
Hotter summers have become the norm from 1980 to present compared to 1951 to 1980 (the base period)

NASA researchers have claimed to find new evidence for everyone's favorite topic: global warming
James Hansen, study leader from NASA's Goddard Institute for Space Studies (GISS), as well as GISS researchers Makiko Sato and Reto Ruedy, have concluded that summer heat waves (mainly in the U.S. Midwest) have become the norm over the last 30 years compared to a base period 30 years before 1980 -- and it's because of global warming. 
Their study works like this: the team collected mean summer temperatures from 1951 to 1980. This was considered the base period for the study. They then looked at the surface temperature data from the last 30 years (1980 until now) to determine whether extreme heat events were increasing. 
From there, the team wanted to see how much heating and cooling occurred in both time periods. To do this, they used a bell curve, which is a common tool that places the middle ground at the top of the bell (for instance, if this were a grading curve, a "C" would be at the top while the next tier down on each side would be a "B" and a "D," and the bottom of the bell would be an "A" and an "F). In this case, the top of the bell would be mean temperature, the next tier down would be "cold" on one side and "hot" on the other, then "very cold" and "extremely cold" on one side moving down while "very hot" and "extremely hot" are moving down the bell on the other side. 
Researchers then applied mean temperatures from 1980 until present, and found that 1980s, 1990s and 2000s fell more to the hot side than cold. The curve widened and flattened as well, which means there was a broader range of variability. This is important because Hansen once predicted that global warming's connection to extreme events would become more apparent in the decades from 1980 to present, but natural variability can play a role too and actually mask the trend. It was important to distinguish the two. 
This wider curve created the new "extremely hot" category, which was barely there in the base period. However, hot has become considered normal in the last 30 years. To be more specific, 75 percent of land area on Earth had "hot" summers in the last decade alone, where only 33 percent had "hot" summers from 1951 to 1980 total. 
According to the researchers, an "extremely hot" summer is considered a mean summer temperature that is experienced by less than one percent of Earth's land area during the base period. But since 2006 alone, approximately 10 percent of land area across the Northern Hemisphere had a summer like this. 
"This summer, people are seeing extreme heat and agricultural impacts," said Hansen. "We're asserting that this is casually connected to global warming, and in this paper, we present the scientific evidence for that."
The study noted "extremely hot" summers in other areas besides just the U.S. Midwest, like Texas, Mexico and Oklahoma in 2011 and Eastern Europe, Western Asia and the Middle East in 2010.
This study was published in the journal Proceedings of the National Academy of Sciences

Source: Science Daily

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GLobal Warming
By Jay Mack on 8/7/2012 2:59:01 PM , Rating: 3
Of course, anything getting hotter is warming. It's a trivial observation. The issue is, whether it is attributable to man made CO2 EMISSIONS and, concurrently, whether Cap and Trade legislation will reverse it, assuming it is undesireable.

But if it is man made, which it may not be, it is likely attributeable to deforestation, primarily in the third world, and/or excessive pavement, highways, roads and parking lots, everywhere. Forests normally sink CO2. Pavement, the heat island effect, is local, but as the locality becomes larger, the effect becomes universal.

Cap and trade will not change the weather. It just makes Al Gore wealthy. And besides, I love this weather we're having.

RE: GLobal Warming
By amosbatto on 8/9/2012 4:26:07 PM , Rating: 2
NASA has broken down the sources of climate forcing which is causing global warming (uncertainty ranges are listed in parentheses):

===Forcing in Watts per m2 of atmosphere:===
Greenhouse Gasses:
CO2: 1.4W (+-0.2W)
CH4: 0.7W (+-0.2W)
CFCs: 0.35W (+-0.05W)
Tropospheric Ozone: 0.3W (+-0.15W)
N20: 0.15W (+0.05)

Other Anthropogenic Forcings:
Tropospheric aerosols: -0.4W (+-0.3W)
Forced cloud changes: -1W (+0.5W,-1W)
Land cover alternations: -0.2W (+-0.2W)

Natural Forcings:
Sun: 0.4W (+-0.2W)
Volcanic Aerosols: 0.2W to -0.5W


There is scientific debate about the exact percentage of CO2, CH4 and N2O which is man made, but look at how these gases have increased between 1750 and 2007 in the atmosphere:
CO2: from 280 ppm to 396 ppm
CH4: from 700 ppb to 1745 ppb
N20: from 270 ppb to 314 ppb
CFC-12: from 0 to 533 ppt

What is clear is that most of the increase in these gasses is coming from humans and is not natural. Anthropogenic greenhouse gas emissions increased from 28.7 to 49.0 gigatons of CO2 equivalent between 1970 and 2004. Deforestation and decay of biomass caused 17.3% of the 2004 emissions, whereas fossil fuel use caused 56.6% of the 2004 emissions. See:

So all your speculation is rubbish. Most climate change is caused by humans who burned fossil fuels which creates CO2. Third world deforestation is a minor factor, but not the major factor. As for heat islands, they are are also a small factor, but mostly localized. When climate scientists calculate global average temperatures, they look at a wide range of data from many locations over a large time span. They are very careful to not let localized conditions govern their averages (as you would realize if you took the time to read any of their literature).

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