What is Climate Change?

The term climate change is often used interchangeably with the term global warming, but according to the National Academy of Sciences, - the phrase 'climate change' is growing in preferred use to 'global warming' because it helps convey that there are [other] changes in addition to rising temperatures."

Climate change refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). Climate change may result from:

    * natural factors, such as changes in the sun's intensity or slow changes in the Earth's orbit around the sun;
    * natural processes within the climate system (e.g. changes in ocean circulation);
    * human activities that change the atmosphere's composition (e.g. through burning fossil fuels) and the land surface (e.g. deforestation, reforestation, urbanization, desertification, etc.)

What is Global Warming?

Global warming is an average increase in the temperature of the atmosphere near the Earth's surface and in the troposphere, which can contribute to changes in global climate patterns. Global warming can occur from a variety of causes, both natural and human induced. In common usage, "global warming" often refers to the warming that can occur as a result of increased emissions of greenhouse gases from human activities.
Climate Change or Global Warming?, Basic Information, 2008, Environmental Protection Agency.

For millions of years, the Sun's energy has nourished the Earth, generating and sustaining all plant and animal life on the planet. A large amount of that energy bounces back into space and some of it is captured by the atmosphere, maintaining warmth and natural balance.
That harmony has been unbalanced by human beings. Our consumption of coal, petrol, diesel, etc, and other human activity such as mining, clearing forests for wood, even agriculture, generates carbon dioxide (CO2), methane, and other greenhouse gases. CO2 levels in the atmosphere have gone up from 280 parts per million at the time of the Industrial Revolution to about 380 ppm currently. Other gases emitted raise this figure to an equivalent of 440 ppm. These gases don't allow the Sun's heat to escape sufficiently, hence warming the planet, the atmosphere, the land, even the deep oceans. As a consequence, on an average, the Earth is at least 0.76 degrees centigrade (1.4 degrees F) warmer than it was at the time of the Industrial Revolution. Much of this has happened in the last few decades.
The Urgency of Global Warming,  Delhi Platform, August 17, 2007

Global Warming, The Problem

• Global warming refers to the increase in the average temperature of the Earth's near-surface air and oceans in recent decades and its projected continuation.

• The global warming has pushed up average global surface temperatures and the rise has been particularly swift since1976. The U.K. Met Office has predicted that 2007 would be the warmest year on record. The warmest years since 1861 are 1998 and 2005 respectively.

• Average global surface temperatures have risen by 0.7 degrees Celsius since the start of the century. The Intergovernmental Panel on Climate Change (IPCC) report says the rise in global temperatures could be as high as 6.4° C by 2100.

• In 2001, the IPCC predicted that sea levels would rise by between 9 and 88 centimetres by 2100, relative to 1990 levels. The new report says rises could range from 18 cm to 59 cm. But predictions of sea level rise are one of the most contentious areas of the report - very recent research has suggested that rises of up to 140 cm are possible.

• 0.13° C - the amount the atmosphere is warming each decade. 1.3 times as much CO2 is entering the atmosphere compared with just 20 years ago. 3 kilometres - the depth to which the oceans have warmed and 3.1 centimetres - the rise in sea level each decade.

• Global warming is not only an ecological or environmental problem, but very much a socio-cultural, economic and political issue.

Global Warming - An Analysis of Problems and Facts, CEDA Trust, 14/09/2007

What does it mean when there is rise in 1 degree temperature?

Mehar Engineer says, "That all parts of the earth will see the same rise? NO! The simplest way to see what it means is to ask, "Suppose, for some reason, that the temperature around the equator goes up by 1 degree celsius; how much will the Earth's other regions heat up? That they will heat up more is obvious because the earth's climate system, meaning its winds and its ocean currents, are the major parts of a giant machine that redistributes the direct solar energy that the earth gets, from the places where that energy is the most, which is the tropics, to the temperate/polar zones where the direct solar energy is smaller/smallest (the Gulf Stream - I'll say more about it soon - is the most well known part of this massive machine). To cut a long story short, a 1 degree Celsius temperature rise in the Earth's equatorial belt means a 12 degree Celsius rise in temperature at the poles. So, if you hear/read that the Arctic sea ice now breaks up, at its southern edges, earlier and earlier in the year every year, and that when the ice refreezes, during the Northern hemisphere's winter, every year, it fails to refreeze as much as it used to, that 12 to 1 ratio tells you why."
The Urgency of Global Warming,  Delhi Platform, August 17, 2007

What Would be the Effect of Global Warming?

The Urgency of Global Warming,  Delhi Platform, 17/08/2007
Adverse impact of climate change: Exclusive on climate change by Ritu Gupta, Down to Earth, 01/02/2008