Global Warming Facts

By Irina Bright.

This article is part of our Environment section

See the complete list of all our Pollution Articles here.

Global warming facts demonstrate unambiguously that global warming is a very serious issue, and it should be acted upon as a matter of urgency.

Global Warming Facts: What is Global Warming

global warming


Global warming is an increase in the average temperature of the surface of the Earth (air and oceans) over the last 100 – 200 years.


During a 100-year period of 1906 – 2005, the global average temperature rose by 0.74°C.


11 of the 12 years between 1995 and 2006 have ranked among the 12 warmest years since 1850.

More Facts.

The world is now hotter than at any time in the last 800 years. (Ref. 1) Further warming of more than 1°C will make the earth warmer than it has been in a million years. (Ref. 2)


As a result of global warming, during the 20th century sea levels rose by 17 cm (6.7 inches); they rose faster in the 2nd half of this century than in the 1st.

global warming facts, greenland ice meltingGlobal Warming Facts: Greenland Ice Cracking


Snow cover in the Northern Hemisphere declined by 4% between 1920 and 2005.

More Facts.

Ice sheets over Greenland lost almost 250 cubic kilometers of ice in the years between 2004 and 2007.

In March 2002 the vast Larsen B Antarctic ice-shelf dramatically collapsed releasing 5 billion tons of ice that shattered into tens of thousands of icebergs and drifted off into the ocean. (Ref. 3)


The Earth is warmed naturally through the process called the greenhouse effect. During this process certain "greenhouse" gases in the atmosphere trap some energy (heat) emitted by the Earth into space, then re-radiate it back on to the ground and thus warm the planet.


The temperature at the outside of the Earth's atmosphere (i.e. without the greenhouse effect) is −18°C. The average temperature of the Earth, thanks to the greenhouse effect, is +15°C, which makes the planet inhabitable.


The main greenhouse gases are: water vapor, carbon dioxide, methane, nitrous oxide, ozone.


The natural concentrations of greenhouse gases in the atmosphere (which work to keep the planet warm) were pretty much constant during the Holocene – a period that started roughly 11,500 years ago – and before the industrial revolution. They increased dramatically since the advent of the Industrial Age at the start of the 19th century.

More Facts.

Below are the pre-industrial and current concentrations of the main greenhouse gases in the atmosphere: (Ref. 4)

bus pollution, transport pollution Transport is a major man-made cause of greenhouse gas emissions. Photo: Doron Laor
  Pre-industrial Current
Carbon Dioxide (CO2) 280 ppm 387 ppm
Methane (CH4) 700 ppb 1,745 ppb
Nitrous Oxide (N2O) 270 ppb 314 ppb

*   ppm - parts per million
**   ppb - parts per billion

Global Warming Facts: Global Warming Causes


The causes of global warming can be both natural and human-induced. sun, sunset Photo:


The natural sources of the Earth's warming are:

  • increases in the energy output of the sun (as the original source of all energy received by the planet), and
  • changes in the Earth's orbital characteristics such as changes in the shape of the Earth’s orbit around the sun as well as the tilt of the Earth’s axis, which can change the total amount of solar energy received by the planet.


While the greenhouse gases are direct agents of global warming, industry and land use are its fundamental human-induced causes.


The widespread use of fossil fuel-based sources of energy in industry, commercial and private sectors is a major source of greenhouse gas emissions. Carbon dioxide (CO2) is the main greenhouse gas released as a result of fossil fuel burning.

More Facts.

Over the past 100 years, the amount of carbon dioxide in the atmosphere has increased by around 25%. (Ref. 5)


Coal is the dirtiest of all fossil fuels.


Modern agricultural practices employed to breed animals, grow cereals, fruits & vegetables and other foods make land use another significant source of greenhouse gas emissions. The main gases released are methane (CH4) and nitrous oxide (N2O).

deforestation, amazon Global Warming Facts: Amazon deforestation - another source of CO2 emissions.
Photo: Leonardo F. Freitas

More Facts.

17% of all the fossil fuel used in the US in year 2002 went into food production. Between 1950 and 2002, world meat production went from 44 mln. to 242 mln. tons a year. Animal agriculture is responsible for 35-40% of all methane generated by human activity. As of 2007, animal agriculture produced around 100 mln. tons of methane a year. (Ref. 6)


Deforestation is an unwanted by-product of land use activities in tropical countries. It is a source of large amounts of carbon dioxide (CO2) being released into the atmosphere, especially if forest fires are used to clear land for different purposes.


The contribution of the 3 main greenhouse gases released by human activities to the total temperature rise over the next 100 years is projected to be:

  • carbon dioxide – 72%.
  • methane – 19%.
  • nitrous oxide – 9%.

Global Warming Facts: Global Warming Effects

The following global warming effects have already been recorded, or projected to take place in the future.

Extreme weather events.

  • Floods
  • Droughts
  • Heat waves
  • Extreme winter cold and snow fall
  • Tornadoes
  • Extreme storms
  • Tropical cyclones / hurricanes / typhoons

More Facts.

Tropical cyclones only develop at tropical latitudes when sea surface temperatures exceed 27°C. The energy released by a single tropical cyclone in one day would be enough to power the entire industrial production of the US for one year. (Ref. 7)

Potential changes to climate patterns.

sea level Global Warming Facts: Sea levels could rise.
Photo: Storm Crypt
  • Polar region of Northern Hemisphere to be hit hardest by rising temperatures
  • Lands to experience greater warming than oceans
  • Increased precipitation in polar and subpolar regions
  • Decreased precipitation in middle latitudes
  • Oceans to continue to warm for several centuries due to greenhouse concentrations which have already taken place

Effects on global sea levels.

Fact. Global sea levels are expected to increase further along with temperature increases.

Fact. An increase of 2°C would cause complete melting of the Greenland ice sheet and would cause global sea level to rise by 5 – 6 meters. This would submerge many islands and lowland regions, ex. US Gulf Coast, much of the Netherlands and Belgium, major cities – Tokyo, New York, Mumbai, Shanghai, Dhaka.

Fact. Complete loss of the West Antarctic ice sheet (if it were to occur) would lead to a 10.5 m rise in the global sea level.

Effects on physical environment.

central coast flood, australia Global Warming Facts: Central Coast Flooded, Australia.
Photo: Lincoln De Kalb

Below we present some potential events which can take place in the future due to global warming.

Fact. Coastal areas are the parts of the planet that are most vulnerable to the effects of global warming. Rising sea levels would flood many of these lands and negatively affect humans populations inhabiting them. Some island nations would likely need to re-locate altogether.

More Facts. Governments of several island countries are already being forced to think of complete relocation of their populations to other, safer lands. This, for example, is the case for the nations of Kiribati (located in the Pacific Ocean) and the Maldives (located in the Indian Ocean).

Fact. Forests may be lost because of the warmer and drier climate conditions, and otherwise badly affected by global warming, ex. through the growth of pests encouraged by warmer temperatures. Forests themselves may contribute to global warming when they are destroyed, especially by way of forest fires which lead to the release of large amounts of CO2 into the atmosphere.

dry forest, coorg india Global Warming Facts: Dry Forest, Coorg, India.
Photo: Ram Prasanth

Fact. Mountains will experience the melting of their snow cover and retreat and disappearance of glaciers. This will reduce the availability of water that runs off from glaciers during the warmer summer months, thus affecting irrigation of crops and drinking water supplies.

Fact. Oceans are the largest carbon sinks in the world. The increased concentrations of carbon dioxide in the atmosphere force the oceans to absorb more and more of this greenhouse gas. This process has led to ocean acidification which has been blamed for damaging coral reefs and other shell-forming organisms.

More Facts. Oceans hold 50 times more carbon dioxide than the atmosphere. They absorb 30-40% of the carbon dioxide produced by human activity. (Ref. 8)

Fact. Permafrost will also be affected by warmer temperatures. It is expected to "thasw", release significant amounts of methane into the atmosphere and therefore further contribute to global warming.

Effects on Biodiversity & Animals.

coral reefs, thailand Global warming may destroy coral reefs. Photo: Jon Hanson

Fact. Many animal species face a risk of extinction exacerbated by global warming. This, for example, can happen indirectly through the loss of habitat or directly by contracting deadly heat-induced diseases.

Fact. Animals may also be affected by reduced availability of food and water as a consequence of global warming.

Fact. Other effects on animals & plants include:

  • Earlier leaf production by trees
  • Earlier greening of vegetation
  • Changed timing of egg-laying and hatching
  • Changes in migration patterns of birds, fish and other animals
  • Reductions and re-distributions in populations of algae and plankton; this threatens the existence of fish and other animals that rely on algae and plankton for food

Effects on Humans.

Fact. The warmer climate will lead to the reduced availability of water supplies which are crucial for the well-being of human populations.

dead land, drought, lack of water Global Warming Facts: Dead Land.
Photo: Fatih Kocaman

More Facts. Droughts and the lack of sufficient water supplies have already caused possibly one of the worst conflicts in modern human history which occurred in an African country of Sudan, specifically the Darfur region. The conflict, that started in 2003, was preceded by decades of drought, desertification and overpopulation in this country. This situation forced members of the Arab Baggara tribes searching for water for their livestock to travel south, the land populated by non-Arab farming communities, and fight for scarce resources. It is estimated that this war resulted in at least 450,000 deaths.

Fact. The water quality will also be compromised by heavy precipitation events which may contaminate drinking water supplies.

Fact. Temperature rises will cause low productivity yields for food supplies.

Fact. Extreme weather events such as droughts and floods will be destroying agricultural crops.

Fact. Heat-induced spread of viruses & bacteria will make human health another victim of global warming.

More Facts. About 45 percent of the world's population currently lives in areas where the climate is potentially suitable for malaria transmission, and as the planet continues to warm that proportion could increase to 60 percent by century's end. (Ref. 9)

flood, children, cambodia Global Warming Facts: Flood in Cambodia.
Photo: Sean

Fact. Extreme events such as heat waves, floods and tropical cyclones will be a major cause of human deaths.

More Facts. The summer of 2003 in Europe was the hottest since 1500, and in August of that year the heat wave killed 20,000 people in France and thousands more in other parts of Europe. (Ref. 10)

Fact. Many millions will suffer from malnutrition because of shortages in food supply which will lead to weakened immune systems and general health deterioration.

Fact. Habitat loss may be another severe impact of global warming on coastal communities.

Fact. By 2000 global warming was already responsible for 150,000 excess deaths annually. It has been calculated that by 2020 it could kill 300,000 people around the world every year. (Ref. 11)

This article is based on the following previously published articles:
What is Global Warming   •   Global Warming Causes   •   Global Warming Effects

Specific References for This Article.

1. Stow, D. (January/February, 2007). Climate Control: Ocean and Atmosphere Are Intricately Linked. Dorrik Stow Explores Some of the Facts, Effects and Challenges of Global Warming. New Internationalist. Retrieved March 12, 2009 from

2. Hansen, J. E. (2006). Can We Still Avoid Dangerous Human-Made Climate Change?. Social Research, Vol. 73. Retrieved March 12, 2009 from

3. Stow, D. (January/February, 2007). Climate Control: Ocean and Atmosphere Are Intricately Linked. Dorrik Stow Explores Some of the Facts, Effects and Challenges of Global Warming. New Internationalist. Retrieved March 12, 2009 from

4. Greenhouse gas. (March 8, 2009). In Wikipedia, The Free Encyclopedia. Retrieved March 12, 2009 from

5. Stow, D. (January/February, 2007). Climate Control: Ocean and Atmosphere Are Intricately Linked. Dorrik Stow Explores Some of the Facts, Effects and Challenges of Global Warming. New Internationalist. Retrieved March 12, 2009 from

6. Wolfson, M. M. (September, 2007). An Inconvenient Food: The Connection between Meat and Global Warming. USA Today (Society for the Advancement of Education), Vol. 136. Retrieved March 12, 2009 from

7. Stow, D. (January/February, 2007). Climate Control: Ocean and Atmosphere Are Intricately Linked. Dorrik Stow Explores Some of the Facts, Effects and Challenges of Global Warming. New Internationalist. Retrieved March 12, 2009 from

8. Ibid.

9. Deweerdt, S. (May/June, 2007). Climate Change, Coming Home: Global Warming's Effects on Populations. World Watch, Vol. 20. Retrieved March 12, 2009 from

10. Ibid.

11. Ibid.