jaaaman

Nasa on Global Warming: It's the Sun.


NASA News Archive

A new NASA study has found that an important counter-balance to the warming of our planet by greenhouse gases – sunlight blocked by dust, pollution and other aerosol particles – appears to have lost ground.

The thinning of Earth’s “sunscreen” of aerosols since the early 1990s could have given an extra push to the rise in global surface temperatures. The finding, published in the March 16 issue of Science, may lead to an improved understanding of recent climate change. In a related study published last week, scientists found that the opposing forces of global warming and the cooling from aerosol-induced "global dimming" can occur at the same time.

"When more sunlight can get through the atmosphere and warm Earth's surface, you're going to have an effect on climate and temperature," said lead author Michael Mishchenko of NASA's Goddard Institute for Space Studies (GISS), New York. "Knowing what aerosols are doing globally gives us an important missing piece of the big picture of the forces at work on climate."

Nightrider

Originally posted by jaaaman:

I happen to agree with NASA. . . when global warming happens on planets like Mars (for instance), we concede it to be the sun's activities. However, when it happens on this planet, we blame it on environmental factors. . . go figure.

Anyway, (I'm not sure of the exact numbers or dates) the temperature of the Earth has warmed up only about 1 degree in the last 250 years or so. . . that hardly sounds like a case for "global warming" due to environmental pollution.

jaaaman

I am in total agreement with you.



I wonder how our 'green' members here will respond to this news archive from NASA.

baloney_detector

Ummmm...you probably aught to re-read this article since this conclusion that you made (above) is a distortion of what they actually said.

jaaaman

No... the article clearly states that the sun is responsible for the global warming, as greenhouse ozone and aerosols have thinned significantly and have allowed more sunlight in to warm the earths surface.

baloney_detector

From the article:

"The thinning of Earth’s “sunscreen” of aerosols since the early 1990s could have given an extra push to the rise in global surface temperatures."

Now, where exactly in this citation (or elsewhere in this article) does NASA say-or even imply-that the reduction in Earth's aerosols is the SOLE reason why our planet is warming...which is what your added headline (conclusion) implies?

(Hint - It doesn't...because greenhouse gases are ALSO a forcing factor in the Earth's surface temperature. If CO2 and other gases didn't ACT as greenhouse gases, then why should they be called "greenhouse gases" in the first place?)

baloney_detector

I would add that there has never been a documented observation that gaseous CO2 and other greenhouses gases DID NOT act as greenhouses gases.

While we can debate, at this point in time at least, how strong of a role different concentrations of greenhouse gases have in effecting Earth's surface temperature, to conclude that they DON'T play a role is the equivalent of saying that ALL of the previous observations concluding that greenhouse gases ARE greenhouse gasses are incorrect...even though there has NEVER been objective data found to defend that conclusion.

Jaxian

It said all of these things except "the sun is responsible for the global warming."

What it said is this: "Knowing what aerosols are doing globally gives us an important missing piece of the big picture of the forces at work on climate."

It is fact that increased amounts of Carbon Dioxide in the atmosphere will warm the planet. That is not under debate. The debate is about how much it will warm the planet. These findings, if anything, indicate that maybe less of the warming is caused by carbon dioxide than previously thought.

Let's take a look at this graph:

Image:Radiative-forcings.svg - Wikipedia, the free encyclopedia

Look at the two bars labelled "aerosols". These bars estimate the amount of cooling aerosols have had on our planet. The article you posted suggests that these bars really should be 20% shorter. If that is true, then we should expect some of those "heating" bars to be shorter too. However, those bars will not be reduced completely: the warming caused by carbon dioxide must still be very high.

I believe the exact number, in Celcius, is something like 0.6 or 0.7 degrees.

Now, a change like this may not seem significant, but take a look at this graph to see how it compares to years past (the colors are explained below the graph):

Image:2000 Year Temperature Comparison.png - Wikipedia, the free encyclopedia

The current temperature is higher than times before man-made aerosols, which suggests that aerosols are not the primary factor in this change.

I should also say this: the global temperature is not increasing at the same rate everywhere in the world. In land areas, the temperature increase has been greater than over oceans. The temperature increase is especially high over the north and south poles. This means that although the average temperature change may be low, not every place on Earth has experienced such a low change. For most places that people actually live, the change has been high.

Further, this temperature change of less than one degree Celcius is not the real problem. The problem is that scientists think the change is caused primarily by increases in carbon dioxide, and the carbon dioxide in our atmosphere is already very high and is only going to keep increasing. So if they are correct, then future temperature increases will be higher than this.

Also, the primary concerns of global warming include a melting of the polar ice caps (which would flood many areas and perhaps shut down ocean currents, causing ice ages on certain continents), a drying up of groundwater which many places depend on, and increased tropical storms. It does not take a huge temperature change to cause these things.

__________________
-Jaxian

baloney_detector

Those higher temperatures at the poles, particularly at the North Pole, might have profound and magnifying effects on global warming.

Read on:

Thawing Permafrost Could Supercharge Warming, Study Says

Sean Markey
for National Geographic News
June 15, 2006


"Thawing permafrost in the Arctic could play a role in fueling global warming, scientists in Russia and the United States report.

Writing in tomorrow's issue of the journal Science, researchers say that permafrost—the layer of frozen soil in polar regions—traps far more carbon than previously thought.

The scientists warn that if permafrost continues to thaw due to global warming, the process could pump huge amounts of greenhouse gases into the atmosphere, stoking further temperature rises.

"The reservoir is very large and dangerous," Sergey Zimov of the Russian Academy of Sciences in Cherskii said in an email.

Zimov and his U.S. colleagues estimate that frozen soils across a large swath of Siberia and Alaska hold nearly 500 billion tons (454 billion metric tons) of carbon—or two-thirds current atmospheric levels.

Much of that carbon is in the form of plant roots and animal bones that accumulated over thousands of years throughout the soil, which is on average 82 feet (25 meters) thick.

"It's about 75 times the annual fossil fuel emissions by all of humankind," said study co-author Edward Schuur, an ecosystems ecologist at the University of Florida in Gainesville.

"It's a big reservoir. Especially big because right now we don't include it in … these analyses of vegetation [and] soil" used to model carbon cycles and global warming, he said."

Thawing Permafrost Could Supercharge Warming, Study Says

Nightrider

Originally posted by Jaxian:

Don't you agree that the sun is at least one of the forces responsible? I hear what you are saying, but I respectfully disagree. The sun's activity varies over time. . . someday it will expand and swallow the Earth to the point where we'll all have to move to another planet. . . granted that won't be for awhile.

The data in the graph is inconclusive:

Originally posted by Jaxian:

There is a lot of controversy and debate over this graph. . . I referenced something off of Wikipedia which sort of is a counterargument to the graph which you cited:

Hockey stick controversy - Wikipedia, the free encyclopedia

(this is referenced from the article which I cited):

However, I aknowledge that this debate seems to be ongoing, and there are no final conclusions. . . I'm just saying that we should not draw our own conclusions based on the graph which you cited. There's a lot that we don't know, and hopefully, time will sort it all out. . .

Originally posted by Jaxian:

Hence, the reason I posted my own graph. . . there may just be no cause for alarm at this point, since time seems to even things out.

Originally posted by Jaxian:

Most of that is about people getting worked up over nothing. . . I for one believe that the sun is primarily responsible for global warming. However, I prefer to let the scientists sort it out. . . hopefully, they will arrive at the correct conclusions - so we can all relax. . .

I thank you for a well thought out (and articulated) argument. . . while I don't agree, I'm not ruling out the possibility of your assertions. I just think that we shouldn't jump to conclusions. . .

- Nightrider