They are opposites, but that doesn't mean that they cancel out!
Eating fatty food and doing exercise have opposite effects on your weight, but that doesn't mean that if you eat 20 big macs a day and only do a minute's walking as exercise that the exercise will completely negate you stuffing your face!
This is a graph based on data from an older climate model which was published in 2004 in a scientific study by Gerry Meehl and colleagues from the National Center for Atmospheric Research:
http://en.wikipedia.org/wiki/File:Climat...
You can see that greenhouse gases cause warming and global dimming (that's 'sulphate' in the graph) causes cooling. From 1940-1970 the increase in global dimming was as strong as the increase in greenhouse gases, but since then the greenhouse gas effect got much stronger and we saw global warming take off.
Carbon dioxide, the most important cause of warming, lasts a long time in the atmosphere. If you increase the amount of CO2 in the atmosphere, it takes 100+ years for that increase to be undone. Sulphates (also called 'aerosol' in some papers) fall out with rain, so they only last a few weeks to months. Sometimes a bit longer if a volcano puts them there, because its explosion punches through the tropopause and puts them in the stratosphere, where there is no rain. In that case it lasts a few years usually.
So if you keep burning fuel, the CO2 keeps building up, but the aerosol/sulphate keeps raining out. Eventually the CO2 overwhelms the aerosol/sulphate and warming becomes stronger.
This was sped up by more clean-air laws in Europe and the USA where filters are used to reduce the amount of sulphur pollution since it causes acid rain. Now the problem has moved to other countries like India and China.
That sounds a bit like saying because I both spend money and am paid money 'surely each one negates the other, therefore I will neither gain nor lose money'.
I think you need to understand the terms you are using properly. 'Global warming' refers to an increase in the global average temperature of surface air, usually as a consequence of the effects of increased concentrations of 'greenhouse gases'. 'Global dimming' refers to a reduction in the in the amount of the sun's power reaching the surface of the earth as a consequence of increased presence of light-reflective particles or droplets in the air.
If you investigate the causes of the phenomena you are asked to consider, you will soon be able to correct your misunderstandings for yourself.
Global warming partially cancels out the effects of global warming, but not completely. Things could get pretty warm without the effects of global dimming.
it doesnt have an opposite effect.... it ends up causing the same damage. global warming and dimming; both cause the ice caps to melt and the earth heat up. why because if either on of them changes from on to the other it causes a change in temperature and when that happens it can cause friction within the air... the earth still heats up.
Dimming happens with simple cloud cover among other things. The current hurricane in the Philippines is causing dimming. Solar radiation can't happen with that much cloud cover.
global warming is just a theory.
That's not thinking. It's claiming by fiat.
HI, quick question.
I'm doing some work on global warming and global dimming and i was just thinking;
Surely global dimming negates the effects of global warming and visa versa...
Please correct me if i'm wrong!
Ta
