It was always a mistake to name Climate Change "Global Warming".
Greenhouse gases (Carbon monoxide primarily) are the natural product
of burning fossil fuels (oil, natural gas). Releasing them into the
atmosphere can (will, has) change the amount of sunlight reflected
back into space, trapping the energy from that sunlight here on Earth.
This can create a condition of warmer temperatures OVERALL, however,
it is the fact that it is CHANGING the global climate which is the
problem. Certain places on the planet now will experience warmer
climates (polar regions in particular), this can (and is) causing
the polar ice caps to melt, releasing vast quantities of cold water
into the oceans, and, more importantly, disrupting the large ocean
currents (for example, the Gulf stream, a wide swath of relatively
warm waters traveling from the equatorial waters of the southwest
Atlantic, all the way to Ireland and Europe. Large amounts of ice
from the north polar region, like Greenland and Iceland, may cause
the Gulf Stream to simply stop or become much cooler than present.
That flow of warm water is what keeps Ireland "green" and Europe
mostly temperate rather than more like Siberia. So... it's possible
that Global Climate Change could cause part of the Earth (like the
US west coast, inter-mountain region and the Midwest to experience
higher temps and prolonged and more frequent drought, while at the
same time (at least for a few decades), plunge Europe into a winterish
nightmare similar to what happened in 1816 (The year without summer),
when ash from a number of volcanos caused a temporary change in
Earth's albedo (solar reflective index).
Here is a few quotes from an article on the subject :
The amazing weather of 1816 is well documented in the diaries and memoirs of those who endured it. Benjamin Harrison, a farmer in Bennington, Vermont. termed it "the most gloomy and extraordinary weather ever seen." Chauncey Jerome of Plymouth, Connecticut, writing in 1860, recalled "I well remember the 7th of June. . . dressed throughout with thick woolen clothes and an overcoat on. My hands got so cold that I was obliged to lay down my tools and put on a pair of mittens...On the 10th of June, my wife brought in some clothes that had been spread on the ground the night before, which were frozen stiff as in winter. On the 4th of July, I saw several men pitching quoits in the middle of the day with overcoats on and the sun shining bright at the time."
Following a frontal passage, temperatures tumbled dramatically under the onslaught of Arctic air. At noon on June 5, the temperature at Williamstown was 83 degrees. By 7am on the 6th, it had dropped to 45 degrees - the highest temperature recorded for the day. All across central New England, early morning temperatures were the highest recorded for the day.
From June 6 to 9, severe frost occurred every night from Canada to Virginia. Ice was reported near Philadelphia and "every green herb was killed, and vegetables of every description very much injured." In northern Vermont, the ice was an inch thick on standing water while elsewhere in the state icicles were to be seen a foot long... corn and other vegetables were killed to the ground, and upon the high lands the leaves of the trees withered and fell off."
<snip>
http://wchs.csc.noaa.gov/1816.htmHope this help explain things. And, yes, we could see stuff like this
again, without the help of volcanos, and on a more permanent basis
(since volcanic ash precipitates out in a year or two whereas carbon
monoxide could be considered fairly permanent).