What is global warming?

Global warming is defined as the increase of the average temperature on Earth. And as temperatures increase, so do natural disasters.
A UN global warming scenario predicts temparature increases of up to six or seven degress Celsius. / Credits: Reuters

Over the last 100 years, the average air temperature near the Earth’s surface has risen by a little less than 1 degree Celsius, or 1.3 degrees Fahrenheit. Doesn't seem that much, does it? Yet this warming is at least partly responsible for the conspicuous increase in storms, floods and raging forest fires we have seen in recent years, say scientists.

Their data show that an increase of one degree Celsius makes the Earth warmer now than it has been for at least a thousand years.The top 11 warmest years on record were all in the previous 13 years, said NASA in 2007, and the first half of 2010 went down in history as the hottest ever recorded.

Projections from the UN climate change body the Intergovernmental Panel on Climate Change (IPCC) say that global surface temperature will probably rise a further 1.5 to 4.8  degrees Celsius during the 21st century.

That huge range of estimates is due to the amazing complexity of our Earth’s climate system and the uncertainty about whether mankind will fight this warming or continue with business-as-usual.

A certain degree of warming is unavoidable even if we managed to reduce our carbon emissions immediately. Oceans, for example, act as huge heat repositories that follow changes in air temperature with a time lag of decades or even hundreds of years. Melting ice caps reflect less sunlight than previously, so our planet absorbs more and more heat.

Exactly how these changes will influence the warming trend is unclear. All we know for certain is that it’s going to be warmer and that human greenhouse gas emissions are an important reason for this.

Are climate change and global warming one and the same?

In a nutshell: global warming is the cause, climate change is the effect.

Scientists often prefer to speak about climate change instead of global warming, because higher global temperatures don’t necessarily mean that it will be warmer at any given time at every location on Earth.

Warming is strongest at the Earth's Poles, the Arctic and the Antarctic, and will continue to be so. In recent years, fall air temperatures in the Arctic have been at a record 9 degrees Fahrenheit (5 degrees Celsius) above normal, according to the U.S. National Oceanic and Atmospheric Administration.

But changing wind patterns could mean that a warming Arctic, for example, leads to colder winters in continental Europe. Regional climates will change as well, but in very different ways. Some regions like parts of Northern Europe or West Africa will probably get wetter, while other regions like the Mediterranean or Central Africa will most likely receive less rainfall.

But it is not just about how much the Earth is warming, it is also about how fast it is warming. There have always been natural climate changes—Ice Ages and the warm intermediate times between them—but those evolved over periods of 50,000 to 100,000 years.

In the past, climate change was triggered by changes in the sun’s energy output, the changing position of continental plates, or the rotating axis of the Earth itself. Many plants and animals were able to adapt to these slowly changing climates. Even humans have changed their habitat according to the comings and goings of glaciers.

All these so-called natural forcings, however, have been ruled out as causes for the warming visible in the last 30 years. Since 1980, temperatures have risen faster than ever before, as far as scientists can ascertain.

This radical change is leading towards a sudden loss of biodiversity—a dwindling number and variety of plants and animals. Many species simply won’t be able to adapt fast enough. According to the most recent UN assessment, 20 to 30 percent of the Earth's plant and animal species face extinction if the world warms by between 1.5 and 2.5 degrees Celsius.

Even for humans, climate change won’t be a smooth transition to a warmer world, warns the Tipping Points Report by Allianz and WWF. Twelve regions around the world could be especially affected by abrupt changes, among them the North Pole, the Amazon rainforest, and California.

All these facts lead scientists to infer that the global warming we now experience is not a natural occurrence and that it is not brought on by natural causes. They say that responsibility lies with humanity’s carbon emissions.

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Comments (252)

willy wonka: 14.10.2014, 20:02

lol go Mr. sharpes class woohoo

sulaiman: 30.09.2013, 18:02

thankx for giving factual knowledge!!!!

ahmed: 06.03.2013, 17:00

i have to do a report about global warming 1200 words any tips ?????????????? thanks if you answer

riaz61: 24.02.2013, 18:59

I want to say about cuting of trees for construction works is a major reson of climate change

Pat Hansen: 11.02.2013, 22:02

If you believe.
Global warming is caused by carbon emissions. Carbon emissions are caused by burning fossil fuels. The biggest burner of fossil fuels is Cars and Roads. There are many more problems associated with cars and roads as well. They can all be fixed and a huge exciting new dynamic global business will evolve. So why not at the very least consider http://stignz.com/ @STIGNZ or fb Sustainable Transport Initiation Group NZ?

dev dongol: 22.12.2012, 11:55

Dear charles beach:

our earth is blessed with unlimited hydropower. flowing water can run turbines in series. please visit my blog devbahadurdongol.blogspot.com

dev dongol: 14.12.2012, 10:57

Post no. 25 Discovery 3
1. OZONE depletion by CFC (Cl2F2C - dichloro-difluoro-carbon) is impossible, because it is too scarce and too heavy to reach to the ozonosphere.
2. Considering the action of UV, the depletion of Ozone is not possible before the extinction of human race (needs at least 16% O2 in the atmosphere). UV is constantly forming O¬3 (Ozone) out of the Oxygen of the atmosphere, thus reducing the amount of UV reaching the earth and is constantly making up the ozonosphere consumed by millions of jet flights every day. After extinction of human race, vegetation will be denser and thus O2 will be released into atmosphere at higher rate than at present. Thus, O3 depletion is impossible.
Details in the blog: devbahadurdongol.blogspot.com

charles beach: 26.04.2012, 14:22

I am saddened and disappointed in the inability of a significant number of civilzed people to not grasp the urgency of responding to global warming.
Burying your head in the sand doesn't mean it doesn't exist.
At the very least, world-wide beneficial effects will result and many countries working together is a good thing.
Contrary to what many think. Governments need to be elected to serve the majority ... not big business.
Wouldn't it be a tremendous help if we could just stop increasing our use of coal world-wide and dramatically increase wind turbines and solar panels?
Are we not worried about what our grandchildren will think of us - THE IRRESPONSIBLE GENERSTION.

dev dongol: 24.01.2012, 08:41

Dear Gadepalli Subrahmanyam,
The sun is heating the earth since its birth, why GW now only and not concerned 50yrs or before?
Got my email?
Details: devbahadurdongol.blogspot.com

Gadepalli Subrahmanyam: 23.01.2012, 14:01

Sun is supposed to be radiating energy at the surface of earth relentlessly. The quantum of energy is calculated to be 6000 (Six Thousand ) times the energy needs of eartrh, calculated at the per cpaita consumption of U.S.A., which is supposed to be one of the highest. Even if the earth and earthlings aree able to use its single share, 5,999 times that energy is simply absorbed by earth, which means the oceans, land mass and ice caps. The radiation out from the earth's atmosphere is any way there, but this much energy falling on the surface cannot escape and is cuasing global warming, in addition to the carbon dioxide emissions, ozone depletion etc., ad nauseum.

Hence blaming only Man for global warming is not fair.

Gadepalli Subrahmanyam

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