Effects of our Activities(global Warming)

Global warming is the Process that increased thedepletion often are linked in the media, the
average temperature of the Earth, near-surfacerelationship between the two is not strong.
air and oceans. The term global warming is aScientists have stated with 66-90% confidence
specific example of the broader term climatethat the effects of volcanic and human-caused
change, which can also refer to global cooling. Inaerosols have offset some of global warming, and
principle, global warming is neutral as to the periodthat greenhouse gases would have resulted in
or causes, but in both common and scientificmore warming than observed if not for this
usage the term generally refers to recenteffect. Many estimates of aggregate net
warming and implies a human influence. Theeconomic costs of damages from climate change
climate system varies through natural, internalacross the globe, the social cost of carbon (SCC),
processes and in response to variations inexpressed in terms of future net benefits and
external "forcing" factors including solar activity,costs that are discounted to the present, are
volcanic emissions, variations in the earth's orbit Innow available. Peer-reviewed estimates of the
the past 200 years human industrial activity hasSCC for 2005 have an average value of US$43
injected carbon dioxide and other greenhouseper tonne Rising global temperature might cause
gases into the atmosphere, and recently globalforest fires to occur on larger scale, and more
average temperatures have been increasing. Theregularly. This releases more stored carbon into
predicted effects for the environment and forthe atmosphere than the carbon cycle can
human life are numerous and varied. The mainnaturally re-absorb, as well as reducing the overall
effect is an increasing global average temperature.forest area on the planet, creating a positive
The scientific consensus is that these greenhousefeedback loop Projected climate changes due to
gases have been responsible for most of theglobal warming have the potential to lead to
present warming trend. That consensus is notfuture large-scale and possibly irreversible changes
unanimous. The earth has experienced naturalin our climate resulting in impacts at continental
global warming and cooling many times in the past.and global scales. With increasing average global
The recent Antarctic EPICA ice core spanstemperature, the water in the oceans expands in
800,000 years, including eight glacial cycles withvolume, and additional water enters them which
interglacial warming periods much hotter thanhad previously been locked up on land in glaciers,
current temperatures.the time of the last glacialfor example, the Greenland and the Antarctic ice
maximum about 20,000 years ago. Scientistssheets. The sea level has risen more than 120
have studied global warming with computermetres since the peak of the last ice age about
models of the climate. These models are based18,000 years ago. For some time it was hoped
on physical principles of fluid dynamics, radiativethat a positive effect of global warming would be
transfer, and other processes, with someincreased agricultural yields, because of the role of
simplifications being necessary because ofcarbon dioxide in photosynthesis, especially in
limitations in computer power. Some effects onpreventing photorespiration While local benefits
both the natural environment and human life are,may be felt in some regions (such as Siberia),
at least in part, already being attributed to globalrecent evidence is that global yields will be
warming. Although global warming and ozonenegatively affected.