Do you believe in the existence of global warming? Please try to provide good and convincing evidence to your point of view. I need this for a project and want to hear what others have to say about global warming. Thank you!

If you%26#039;re talking about man-made (anthropogenic) global warming, then the answer is yes.

There are many basic scientific facts which can only be explained if the current global warming is being caused by an increased greenhouse effect due to carbon dioxide accumulating in the atmosphere from humans burning fossil fuels.

For example, the planet is warming as much or more during the night than day. If the warming were due to the Sun, the planet should warm a lot more during the day when the Sun has influence. Greenhouse gases trap heat all the time, so they warm the planet regardless of time of day. Another example is that the upper atmosphere is cooling because the greenhouse gases trap the heat in the lower atmosphere. If warming were due to the Sun, it would be warming all layers of the atmosphere.

http://answers.yahoo.com/question/index;...

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...

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.

they never get it wrong.

Wow, the answer above sounds like it had already been written and planned. Mine is not quite as elaborate.

First of all, yes, I think that the climate is warming; however, I do not think that it is abnormal - the earth has gone through many changes in climate over its lifetime and this happens to be of them.

And the fact that this can only be caused by increased carbon dioxide emissions is not true.

Also, it is rediculous to say that this is impossible to recover from - the earth created the ozone at point in time and the atmosphere, are we so arrogant that we think that we have that much influence on something as large as a planet?

Also, it is all good an well to claim global warming when it is 70 in the winter, but where are the global warming shouts when almost the whole us is below 30, and when it is snowing in L.A.?

Personally, I think that it is a lot of propoganda that is driving what will soon be a huge cash cow as consumers flock to paying more for %26quot;green%26quot; - it is cliche and usually if something is so controversial AND makes a lot of money in the process, be very skeptical of the validity of the claims.

The weather does what the weather does. We are having record cold temperatures because the jet stream is dipping down from the arctic bringing frigid air across the entire country. It has nothing to do with global warming or global cooling. The droughts and heat waves this summer were due to a pair of stationary high pressure systems that settled over the south east and sothwest regions of the country. Those high pressure areas pushed away all the moisture channeling down the central plains. These are completely normal, if uncommon weather patterns. There is nothing about them that is outside the Earth%26#039;s normal range of weather patterns. I think all this talk about human generated global warming is the ultimate in human arrogance. We like to think we control the entire world. So when things start to change in ways we do not understand, we think we must be the cause of it. We never step back and think that the Earth existed for 4 billion years without us and will keep existing long after we are gone. The climate has changed many times and will change many more times. If we want to keep living on this wonderful changing planet we%26#039;d better be able to adapt to its changes. Does the planet respond to what we do? Yes. Is it going to permanantly alter the course of the planet? No. The planet is far stronger and more resiliant than the human race. If the climate changes, as it has many times before, then we must change with it to survive. While I don%26#039;t think anything we do will alter this planet%26#039;s natural progression towards whatever climate change awaits it, I think most of the things that are proposed to combat the artificial boogey man of anthropogenic global warming will have generally benificial results if enacted responsibly. More trees, clean air, clean water, energy efficiency, reduction of dependecy on oil. As long as we don%26#039;t bankrupt ourselves getting these things going, they will make life generally better, and can be made economically benificial too. The Key is to quit using scare tactics and start appealing to people%26#039;s economic interests to get these policies working. The build up of greenhouse gases has an effect, but it doen%26#039;t all come from fossil fuels, which are in fact part of the earth%26#039;s carbon cycle and not an unnatural addition. Much of it come from deforestation and agricultural burning. And The CO2 that is in the atmoshere is not going anywhere unless reforestation efforts take place. So cripplig the economy is not going to help reverse this process regardless. But still, the climate is changing; it is a process that is already in motion and beyond our power to stop. And for climate change, let it come, or not. That is up to the Earth itself. Whatever will come we will adapt.

Not on the level they are saying it is happening. It is largely hype. Now before all the tree huggers get up in arms about this and start saying %26quot;Yeah well in the time Bush has been in office the temperature has gone up half a degree%26quot; or whatever, let%26#039;s look at a few points. First and for most, this planet has had rising and falling temperature conditions for millions of years. This has been going on long before man was here. Ever hear of dinosaurs? Notice there aren%26#039;t any around lately? We didn%26#039;t cause that. We have evidence of ice ages we didn%26#039;t cause as well as %26quot;global warming%26quot;. Volcanic activity and a lot of other factors have caused huge swells in the extreme of climate change since the Earth has existed. Now that isn%26#039;t to say that we aren%26#039;t destroying the ozone layer and we aren%26#039;t having some impact on things. History shows though that our planet goes through these cycles naturally and anyone who believes that what is going on with the icecaps melting and global warming, etc, etc. is something new that we caused isn%26#039;t looking at the full story.