Will The Earth Cool Down?

Question

NASA's long range solar forcast is predicting "one of the weakest (solar cycles) in centuries" and the next cycle is starting late. If CO2 remained the same and solar cycle 24 and 25 were duplicates of cycles 5 and 6, would the Earth cool down?

http://science.nasa.gov/headlines/y2006/10may_longrange.htm

http://en.wikipedia.org/wiki/Solar_cycle

Why does temperature correlate better with sunspot cycle length than CO2?

Why did temperatures cool for 30 years after WW2, when CO2 was increasing?

Why was most of the heating in the 20th century prior to WW2 and the greatest increase in CO2?

http://www.sosforests.com/wp-content/postedimages/sunspotcycle.jpg

I am here to learn.

Answer 1

Yes, it's very possible that we will be entering into a cool down period.

CO2 is a result of warming, not the cause. It will be fun to see temps decline while CO2 levels continue to increase. We know from proxy data that CO2 lags temps by some 800 years.

"Climate changes such as global warming may be due to changes in the sun rather than to the release of greenhouse gases on Earth."
"the present warming may be unusual - but a mini ice age could soon follow"
http://news.bbc.co.uk/1/hi/sci/tech/5645...

"The July 2007 issue of Discover magazine gives a glimpse into the real cause of global warming. Henrik Svensmark, director for the Center for Sun-Climate Research at the Danish National Space Center has shown that solar activity is the cause of global warming."
"Svensmark brought the wrath of the United Nations and politically motivated scientists on himself in 1996 when he reported that the sun's activity could explain most or all of the recent rise in the Earth's temperature."
http://www.newsreview.info/article/20070...

"World weather is going crazy again. But it has little to do with global warming caused by greenhouse gasses and plenty to do with variations in solar activity."
"Indeed the entire concept of rising sea levels caused by melting ice caps --may be only a storm of hype."
"Back in 1841, famous Antarctic explorer Captain Sir James Clark Ross made his mark on a little island near Port Arthur, Tasmania. That is, he literally marked the mean level of the tides on a sandstone cliff face. Incredibly, that the mark is one inch above the current mean tide level today"
http://homepage.eircom.net/~gulufuture/f...

"It is known as the Little Ice Age. Bitter winters blighted much of the northern hemisphere for decades in the second half of the 17th century. The French army used frozen rivers as thoroughfares to invade the Netherlands. New Yorkers walked from Manhattan to Staten Island across the frozen harbour. Sea ice surrounded Iceland for miles and the island's population halved. It wasn't the first time temperatures had plunged: a couple of hundred years earlier, between 1420 and 1570, a climatic downturn claimed the Viking colonies on Greenland, turning them from fertile farmlands into arctic wastelands."
"Could the sun have been to blame? We now know that, curiously, both these mini ice ages coincided with prolonged lulls in the sun's activity - the sunspots and dramatic flares that are driven by its powerful magnetic field."
"Now some astronomers are predicting that the sun is about to enter another quiet period. "
http://environment.newscientist.com/arti...

"St. Petersburg, Jan 17 (RIA Novosti) Rising levels of carbon dioxide and other gases emitted through human activity, generally believed to trap heat in the earth's atmosphere, are an effect rather than the cause of global warming, according to a prominent Russian scientist."
"Habibullo Abdusamatov, head of the space research laboratory at the St. Petersburg-based Pulkovo Observatory, said global warming stems from an increase in the sun's activity."
http://in.news.yahoo.com/070117/43/6b7zr...

Answer 2

Absolutely false. The earth has been cooling since 1998. The only way to say it has continued warming is to manipulate data. In 1976 we were "headed for a new ice age by 1990". That failed to happen. In 1989 we were "headed for global warming which will cause droubt and famine worldwide by 2000." That failed to happen. In 2006 it changed to "climate change". Now any change in temp or precipitation is caused by "climate change" which is "man made. Truth is its complete hogwash. Its a computer model that lacks the necessary data to project the weather 1 week from now much less 20 years from now.

Answer 3

That is the trillion dollar question Larry. The one simple fact is we do not know how well TSI correlates with the solar magnetic field variation, we do not have enough data. In fact we do not even know how much UV radiation variation that has even occurred over the last thirty years of the TSI record, and it's effect on the climate. There is however a developing theory with data to support it, that relates the Sun's magnetic field with Cosmic Ray flux, as Mr. Jello pointed out. If the Sun's magnetic field grows very weak as predicted at the peak of Solar cycle 25, there is evidence to suggest that the troposphere will be exposed to more galactic cosmic ray energy thereby creating more clouds and directly reducing incoming solar energy. A mere 1 percent increase in global cloud cover will likely more than negate any forcing associated with Anthropogenic Emissions. That coupled with a probable significant decrease in TSI, will almost certainly lead to a much cooler climate. And since even the most cultist AGW zealots admit that an increase in solar energy lead to the warming which allowed us to emerge from the LIA, it would appear that your question should not be out of the realm of possibility even for the AGW faithfull.

There is also a prediction of a cooler climate by the late Dr. Theodor Landscheidt, he was a solar phycisists, that correlated climatic change to cycles realated to the configuration of the outer planets and their effect on the center of mass of the solar system. Who actually predicted the last two El-Nino's years before they occured.

If the climate cools by the middle of this century as predicted, the economic and physical hardships faced by humanity will make global warming look like a bad thunderstorm.

EDIT:

One of the problems with Earths energy budget is that when a large Volcanic erruption occurs, it has a short term cooling effect (2 years) but if the volcano emits SO2 into the stratosphere, it destroys significant quanities of Ozone. That is why the stratosphere always shows an immediate warming after a volcano, but then cools to a much cooler state after an erruption. The stratospheric cooling is a result of ozone depletion. Ozone depletion allows more UV energy to reach Earths surface, and contibutes to global warming. Some believe that the stratospheric cooling is a result of CO2 absorption of IR energy in the troposphere, but since the stratospheric cooling coincides with volcanic erruptions that cannot be the case. Consequently there were no siginificant volcanic erruptions between WWII and the Agung erruption.

http://hadobs.metoffice.com/hadat/images/update_images/global_upper_air.png

Answer 4

The causes of current global warm, AND trends are outside the conventional correction theories. something far simpler is needed to make these effects slow to a revers able rate. I could estimate 10 years but who would take that seriously. Much less want to do anything about it. Guess we could buy more sun block until THAT becomes basting sauce for the roaches.

Answer 5

The variation in the sun's output is not relevant to the current global warming problem because the energy that the sun actually gives to the lower atmosphere is pretty much constant anyway (at least over the kind of time-scales we're having a problem over). There is a lot of variation in EUV and X-ray output but the thermosphere blocks them (and it doesn't really affect the temperature down below anyway).

To have the earth cool down you'll have to either remove some CO2 or block some of the sunlight.

Answer 6

No. The solar cycles deal with things like sunspot activities. Their effect on the Earth's temperature is small. See:

http://environment.newscientist.com/channel/earth/climate-change/dn11650
http://solar-center.stanford.edu/sun-on-earth/FAQ2.html
http://www.realclimate.org/index.php/archives/2005/07/the-lure-of-solar-forcing/

The effects of greenhouse gases are much stronger, and overpower natural forces at present. See:

Meehl, G.A., W.M. Washington, C.A. Ammann, J.M. Arblaster, T.M.L. Wigleym and C. Tebaldi (2004). "Combinations of Natural and Anthropogenic Forcings in Twentieth-Century Climate". Journal of Climate 17: 3721-3727

summarized at:

http://www.globalwarmingart.com/wiki/Image:Climate_Change_Attribution.png

Good website for more info on global warming:

http://profend.com/global-warming/

EDIT - Your questions about the causes of warming at various times in the 20th century are answered in detail in the Meehl paper, and quickly by the summary. It's complicated but roughly natural forces combined with some greenhouse gases controlled climate in the early 20th century. In mid century pollution blocking the Sun balanced that trend and temperatures steadied. Recently the huge increases in greenhouse gases caused by huge consumption of fossil fuels have dominated everything else.

It's not simple, but it's what the data says. "Logic" just isn't enough to understand this, you need to look at the numbers. Scientists do just that, which is why the vast majority of them accept this explanation.

Answer 7

Well, yeah, possibly, if CO2 remained the same the numbers could be massaged sufficiently to permit that result. Since the CO2 is not going to stay the same, I'm having trouble seeing the point of the question.

Answer 8

Short term cooling (within decades) isn't possible even if we were to immediately stop the emission of all greenhouse gases.

There are many different grenhouse gases and they have varying 'residency periods' or 'atmospheric lifespans' - the length of time they remain in the atmosphere and contribute to global warming. It varies from 4 days for water vapour to 31,500 years for sodium hexaflouride. The primary manmade greenhouse gas and largest contributor to anthropogenic global warming is carbon dioixide, this has a residency period of 115 years.

It's not as simple as that, there are natural cycles which in time remove certain greenhouse gases. For example, if we never added any more CO2 to the atmopshere the concentration would start to drop as nature mopped up the excess. Whilst contributing to GW for the next 115 years the concentration of manmade CO2 would decline and the overall contribution would tend to zero.

The solar cycles you're referring to are the 11 year sunspot cycles. The maximum deviation from the mean of any sunspot cycle, be it a very strong or a very weak one, is small, it's a variation of approx one two-thousandth from the mean (variance range is 1.3 from a mean of 1366 (Watts per square metre per year)).

When sunspot activity falls to zero there is a drop of approx 0.65 W/m2/yr in solar irradiance. This 'forcing' is more than compensated for by the additional burdon of greenhouse gases.

Historically there have been prolonged periods of almost no sunspot activity such as the Maunder Minimum, over hundreds of years these events lead to global cooling if there are no exacerbating circumstances. Today there are exacerbating circumstances that more than compensate for any reduction in solar irradiance.

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RE YOUR ADDED DETAILS:

A) Temps do not correlate with sunspot cycles. Sunspot cycles are approx 11 years, if temps correlated we'd have 5½ years warming followed by 5½ years cooling. Temps correlate with prolonged perionds of increased or decreased solar activity - as explained above this can lead to a change in solar irradiance of as much as 0.65 Wm²yr. Over periods of hundreds of years the cumulative effect is noticeable, over years or decades the effect is small.

Historically solar and terrestrial cycles have been the primary drivers of climate change but these changes have been very slow and over long periods of time. Today temps are rising far beyond any possible natural circumstances.

B) Temps cooled from the 1940's to 1970's due to 'global dimming'. Back then we emited huge quanities of pollutants into the atmosphere including sulphur dioxide (mainy from power stations, burning coal and burning 'town gas' or 'coal gas'). SO2 is an atmospheric coolant as it reflects solar radiation back into space.

Following the Great Smog of 1952, which at it's peak claimed the lives of thousands of Londoners a day, the first of the Clean Air Acts were past, in the years that followed more Clean Air Acts were passed such that by the late 60's / early 70's levels of SO2 and other pollutants began to fall.

In the aftermath of massive volcanic eruptions the planet cools because of the emission of vast amounts of SO2. Following the 1991 eruption of Mt Pinatubo the world cooled for a few years. More notable was the immense eruption of Mt Tambora in 1815, the following year has gone down in history as 'the year without a summer'.

C) Most of the heating of the 20th C comes after WW2. The 1900 10 year global mean temp was 13.731°C, by 1939 it was 14.022°C, a rise of 0.291°C in 39 years. In the last 39 years temps have gone up from 13.987°C in 1968 to 14.608°C in 2007 - a rise of 0.621°C and more than double the rise prior to WW2.

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I know you'd prefer answers that say the world will cool down and that temps correlate with sunspots etc but to do so would be irresponsible, inaccurate and misleading. At the end of the day this stuff is my line of work, I know what I'm talking about and proivide answers based on documented scientific fact.

My apologies if I misjudged you, some people are very close-minded and systematically ignore anything and everything that doesn't conform to their preconceived ideas.

Answer 9

We are talking about global warming! How can the Earth cool down!

Answer 10

You should sleep in a refrigerator now!!