CLIMATE CHANGE & GLOBAL WARMING

WHAT IS CLIMAtE CHANGE?

Climate change refers to the variation in the Earth’s global climate or in regional climates over time, whether over decades or millions of years. Common use of the term “climate change” is mainly concerned with ongoing changes in modern climate, including the rise in average surface temperature known as global warming.

In some cases, the term "climate change" is used in a way that assumes it is caused by humans, as in the United Nations Framework Convention on Climate Change. However the term "climate change" more commonly assumes that human causes are one of other factors.

WHAT causes CLIMAtE CHANGE?

Changes in climate may come from processes internal to the Earth, be driven by external forces such as variations in sunlight intensity or, most recently, be caused by human activities.

Climate change factors

Variations within the Earth’s climate
The effect of glaciers
Variations in the oceans
The memory of climate

Non-climate factors driving climate change

Greenhouse gases
Movement of the Earth's tectonic plates
Variations in the Sun
Variations in the Earth's orbit
Volcanic activity

Human influences on climate change

Fossil fuels
Aerosols
Land use.

 

WHAT IS GLOBAL WARMING?

Global warming refers to the well-documented increase of global temperatures. The majority of scientists agree that most of the observed warming over the last 50 years is likely to have been caused by human activities”. A small number of scientists still dispute this. The precise degree to which humans have caused global warming is still under debate as well.

Although global warming is sometimes used interchangeably with climate change, global warming is more correctly one aspect of climate change.

Why are people so worried about GLOBAL WARMING?

Global warming is already having serious impacts on humans and the environment in many ways. An increase in global temperatures can in turn cause other changes, including a rising sea level and changes in the amount and pattern of precipitation. These changes may increase the frequency and intensity of extreme weather events, such as floods, droughts, heat waves, hurricanes, and tornados.

Other consequences include higher or lower agricultural yields, glacial retreat, reduced summer stream flows, species extinctions and increased spread of disease. Warming is expected to affect the number and magnitude of these events; however, it is difficult to connect particular events to global warming.

Although most studies focus on the period up to 2100, warming (and sea level rise due to thermal expansion) is expected to continue past then, since CO2 has an estimated atmospheric lifetime of 50 to 200 years.

Many scientists are also concerned about feedback loops, where certain factors could lead to greatly increased rates of global warming. One example are tundra landscapes. As tundra melts, previously frozen plant matter can decay and release huge amounts of CO2 into the atmosphere. As this warms the Earth, more tundra will melt and could lead to a feedback loop in global warming.

debate among scientists over GLOBAL WARMING

Only a small minority of climate scientists disagree that humanity’s actions have played a major role in recent global warming. However, the uncertainty is more significant regarding how much climate change should be expected in the future. There is also a hotly contested political and public debate over policies that deal with predicted consequences, what should be done to reduce or reverse future warming, and how to deal with the predicted consequences of global warming.

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This information is licensed under the GNU Free Documentation. It is derivative of articles Climate Change, Global Warming and related environmental issues at http://en.wikipedia.org