We know it%26#039;s warming, and we%26#039;ve measured how much:
http://www.epa.gov/climatechange/science...
Scientists have a good idea how the Sun and the Earth%26#039;s natural cycles and volcanoes and all those natural effects change the global climate, so they%26#039;ve gone back and checked to see if they could be responsible for the current global warming. What they found is:
Over the past 30 years, all solar effects on the global climate have been in the direction of (slight) cooling, not warming. This is during a very rapid period of global warming.
http://news.bbc.co.uk/2/hi/uk_news/62902...
http://www.pubs.royalsoc.ac.uk/media/pro...
A recent study concluded:
“the range of [Northern Hemisphere]-temperature reconstructions and natural forcing histories…constrain the natural contribution to 20th century warming to be %26lt;0.2°C [less than one-third of the total warming]. Anthropogenic forcing must account for the difference between a small natural temperature signal and the observed warming in the late 20th century.”
http://www.pnas.org/cgi/content/full/104...
You can see this in the third graph here, where the dotted lines are just from natural causes, and the full lines are natural + human causes:
http://www.pnas.org/content/vol104/issue...
If that’s not enough to convince you the Sun isn’t responsible, consider the fact that no scientific study has ever attributed more than one-third of the warming over the past 30 years to the Sun, and most attribute just 0-10% to the Sun.
http://answers.yahoo.com/question/index;...
So the Sun certainly isn%26#039;t a large factor in the current warming. They%26#039;ve also looked at natural cycles, and found that we should be in the middle of a cooling period right now.
%26quot;An often-cited 1980 study by Imbrie and Imbrie determined that %26#039;Ignoring anthropogenic and other possible sources of variation acting at frequencies higher than one cycle per 19,000 years, this model predicts that the long-term cooling trend which began some 6,000 years ago will continue for the next 23,000 years.%26#039;%26quot;
http://en.wikipedia.org/wiki/Milankovitc...
http://www.sciencemag.org/cgi/content/ab...
So it%26#039;s definitely not the Earth%26#039;s natural cycles. They looked at volcanoes, and found that
a) volcanoes cause more global cooling than warming, because the particles they emit block sunlight
b) humans emit over 150 times more CO2 than volcanoes annually
http://volcano.und.edu/vwdocs/Gases/man....
So it%26#039;s certainly not due to volcanoes. Then they looked at human greenhouse gas emissions. We know how much atmospheric CO2 concentrations have increased over the past 50 years:
http://en.wikipedia.org/wiki/Image:Mauna...
And we know from isotope ratios that this increase is due entirely to human emissions from burning fossil fuels. We know how much of a greenhouse effect these gases like carbon dioxide have, and the increase we%26#039;ve seen is enough to have caused almost all of the warming we%26#039;ve seen over the past 30 years (about 80-90%). You can see a model of the various factors over the past century here:
http://en.wikipedia.org/wiki/Image:Clima...
This is enough evidence to convince almost all climate scientists that humans are the primary cause of the current global warming. 43% 10 Votes
There%26#039;s no sudden hype, it%26#039;s just a long set of scientific studies building upon the previous knowledge and the new findings.
Any reasonably educated and open-minded person can see that:
1) Global temperature is rising. No temperature data sets disagree with the measured trend of 120+ years of global warming (or they%26#039;d be trotted out regularly in these discussions). Zero. Zilch. Nada. None.
2) The 750°K temperature of Venus, with its atmosphere of 90% carbon dioxide, is strong evidence supporting greenhouse gas theory.
http://www.ias.ac.in/resonance/Mar1996/p...
3) It%26#039;s been confirmed through carbon isotope analysis that mankind has increased CO2 levels significantly, as temperatures rose.
Since we know that CO2 can cause several hundred degrees of warming, since we%26#039;ve observed that mankind has increased CO2 and earth%26#039;s temperature rose, and since we know that climate change can dramatically affect our food supplies, common sense dictates that we do something to moderate the cause.
Unfortunately the IPCC reports fail to accurately reflect scientists%26#039; views. The process allowed countries with a clear agenda such as Saudi Arabia and the Bush Administration to edit the text:
%26quot;The scientific consensus most people are familiar with is the IPCC%26#039;s %26quot;Summary for Policymakers%26quot; reports. But those aren%26#039;t a majority opinion. Government representatives participate in a line-by-line review and revision of these summaries. So China, Saudi Arabia and that hotbed of denialism -- the Bush administration -- get to veto anything they don%26#039;t like. The deniers call this %26quot;politicized science,%26quot; suggesting the process turns the IPCC summaries into some sort of unscientific exaggeration. In fact, the reverse is true. The net result is unanimous agreement on a conservative or watered-down document.
http://www.salon.com/news/feature/2008/0...
As a result, the emerging evidence tends to be worse than forecasted, indicating that the urgency and severity of the problem may be severely underestimated.
- Three papers published after the IPCC reports concluded that sea level rise this century will be much higher than the IPCC reports:
%26quot;Instead of sea levels rising by about 40 centimetres, as the IPCC predicts in one of its computer forecasts, the true rise might be as great as several metres by 2100. That is why, they say, planet Earth today is in %26#039;imminent peril.%26#039;%26quot;
- One scientist forecasted last year that the Arctic could be nearly ice free by 2012. That%26#039;s dramatically sooner than past estimates.
- There is a 50 percent chance Lake Mead will run dry by 2021 and a 10 percent chance it will run out of usable water by 2014...
- One scenario examined by the Pentagon examines the possibility of food riots, anarchy, and possibly nuclear war by 2020.
In fact, the cost of food has skyrocketed in the past year and food riots have already started:
http://www.climatechangenews.org/nFood.h...
The World%26#039;s Growing Food-Price Crisis - TIME
%26quot;Soaring prices of staples — which have risen about 75% since 2005, driven by growing demand, rising oil prices and the effects of global warming — have sparked riots in several countries, as people reel from sticker shock and governments scramble to feed their people.%26quot;
Fresh records for price of wheat- BBC News
%26quot;Wheat prices have hit record levels as supplies dwindle, raising concerns about growing food inflation. Reports of a drought in Northern China, where most of the country%26#039;s wheat is grown, also pushed prices higher. Extreme weather has already damaged crops in other parts of the world and US wheat inventories are expected to fall to their lowest level for 60 years.%26quot;
Many other recent observations reveal that the IPCC has been underestimating impacts:
- Since 2000, carbon dioxide emissions have grown faster than any IPCC model had projected.
- The temperature rise from 1990 to 2005 -- 0.33°C -- was %26quot;near the top end of the range%26quot; of IPCC climate model predictions.
- %26quot;The recent [Arctic] sea-ice retreat is larger than in any of the (19) IPCC [climate] models%26quot; -- and that was a Norwegian expert in 2005. Since then, the Arctic retreat has stunned scientists by accelerating, losing an area equal to Texas and California just last summer.
- %26quot;The unexpectedly rapid expansion of the tropical belt constitutes yet another signal that climate change is occurring sooner than expected,%26quot; noted one climate researcher in December.
Denialists like to state that we%26#039;ve been coming out of an ice age for some time, and that there%26#039;s no evidence that current warming is unusual. That%26#039;s simply untrue:
New Research Confirms Antarctic Thaw Fears - Spiegel Online
http://www.alertnet.org/thenews/newsdesk...
%26quot;The paper also states that the thickness of the Pine Island Glacier has shrunk by an average of 3.8 centimeters annually over the past 4,700 years. Satellite measurements taken between 1992 and 1996, though, show a loss of 1.6 meters in thickness per year on the Pine Island Glacier -- a figure that represents 42 times the average melt of the past 4,700 years.%26quot;
We have more than enough data to act on, and very little time to act on it to prevent massive damage to our global food supplies. 0% 0 Votes
http://www.aip.org/gov/policy12.html
http://www.geosociety.org/positions/inde...
http://dels.nas.edu/dels/rpt_briefs/clim...
http://earthobservatory.nasa.gov/Library...
This is an offer of more than %26quot;magic beans%26quot; as one poster with no data suggests. This is knowledge from respected, mainstream science.