and how do human actions contribute towards it
The earth has always heated up or cooled down slowly. We can take ice cores from the Antarctic to see global weather conditions for the last 10,000 years! It's on a warming trend now, but in all the time we can see, it's never heated up nearly as fast as it has over the last 20 years or so.
Scientists believe this is because of the amount of carbon dioxide in the atmosphere (CO2). For 200 years now we have been dumping CO2 into the air by burning fossil fuels Much of the carbon on earth was 'sequestered' in coal, petroleum, and natural gas. When we burn these things the carbon goes into the atmosphere. Studies have shown that the amount of carbon in the atmosphere is many times what it was a few centuries ago.
Decades ago, climate scientists said that the global warming would make deserts grow, it would destroy good farming lands and forests, etc. All that is happening, but slowly enough that deniers can deny. They also said we'd see much stronger weather phenomena, bigger and more frequent hurricanes, tornadoes, typhoons, monsoons, etc., even blizzards. And we're certainly seeing that today
There is no simple answer to your question. Yes, humans do "contribute" to global warming by putting certain chemicals into the atmosphere, such as methane, or destroying the ozone layer with other harmful chemicals, but what we are doing is nothing compared to other natural effects. For instance, Volcanoes put a massive amount of CO2 and other chemicals into the air, the same ones that we are putting into the air, the only difference is placement within the atmosphere. When they are higher, they cool the atmosphere instead of heating it. But this is all a cycle, the earth is either cooling down or heating up at any point, and we are simply in a heating stage of history
see the source-NASA
1.. CO2 is a greenhouse gas, that has been known for over a hundred years.
2. Climate responds to greenhouse gases, and it does not care if that CO2 is natural or not.
3. CO2 is now the highest it has been in 1/2 million years
4. The changes in climate today are outside the 'natural' cycles and variability.
5. humans contribute by adding more CO2 by burning coal, oil and gas.
it's a lot simpler to deny it exists and live in a parallel universe like Sagebrush and MAXX.
Human activities DO NOT significantly contribute to global warming, and this is according to some of the top climate scientists in the field.
The Climate is controlled by solar variance, not CO2 gases. But don't take my word for it, see what the experts say.
Top climate scientists say there is no man-made Global Warming.
The Great Global Warming Swindle
http://www.rkm.com.au/ANIMATIONS/carbon-... <== here's the physics.
http://web4.audubon.org/globalwarming/im... <== this is why CO2 is a problem.
http://www.rsc.org/images/CA1_tcm18-1379... <== Word doc. Page 6 shows where H2O and CO2 intercept different wavelengths
http://upload.wikimedia.org/wikipedia/co... <== Note that CO2 intercepts a different wavelength than water. In addition, as CO2 warms the oceans, more water evaporates, increasing it's effectiveness.
http://www.school-for-champions.com/scie... <== melting of the Siberian tundra is a global warming time bomb.
http://fora.tv/2009/08/18/A_REALLY_Incon... <== This is an hour long, but is very good.
It has never been proven that they do.
AGW refers to when man intervenes in the earth's temperature and causes that temperature to rise unnaturally.
There is nothing in man's power that he can do to change the global temperature. No one can prove that there is, or at least they haven't come close, so far. And I doubt that they ever will.
When too many people leave the furnace on too long
They don't
What is global warming?
and how do human actions contribute towards it
