Global warming and climate change refer to an increase in average global temperatures. Natural events and human activities are believed to be contributing to an increase in average global temperatures. This is caused primarily by increases in “greenhouse” gases such as Carbon Dioxide (CO2).

Global warming is the increase in the average temperature of the Earth's surface air and oceans since the mid-twentieth century and its projected continuation.

 

The estimated effects of global warming on the environment and for the life of human beings are huge and varied. Although it is really difficult to attribute specific natural phenomena to long-term causes, but some effects of recent climate chnge may already be occurring. Rising sea levels, glacier retreat, Arctic shrinkage, and altered patterns of agricuture are cited as direct consequences, but predictions for secondary and regional effects include extreme weather events, an expansion of tropical diseases, changes in the timing of seasonal patterns in ecosystems, and drastic economic impact. Concerns have led to political activism advocating proposals to mitigae, eliminate, or adapt to it.

With global warming on the increase and species’ habitats on the decrease, the chances for various ecosystems to adapt naturally are diminishing.

Greenhouse Effect is the major contributor to the Global Warming.

In Central Siberia the temperature can fall to as low as -70°C and the permafrost is 1.5 km thick. During the last four decades alone, the air temperature in winter has risen by 4°C, while the river's spring temperature has increased by 2°C since the 1980s.

In this study, the scientists, led by France's National Scientific Research Centre (CNRS), looked at data, including photographs, satellite images and ground data, going back to the 1960s to see how these temperature increases had affected the river.

They found that more of the upper layer of permafrost was melting every year, and this melt water was flowing into the Lena. This increased the amount of water in the river, which in turn caused greater erosion of the banks. This erosion poses a serious threat to the urban centres and industrial installations situated along the river.

Furthermore, the increased water flow also affects the islands in the river. The heads of these islands, which bear the brunt of the river's strength, are eroding faster. As a consequence, greater quantities of sediment are being moved around the river, where they form sandbanks. In some cases, these sandbanks have rendered certain channels impassable for shipping.

Climate change is having a major impact on one of the longest rivers in the world, the 4,400 kilometre Lena, which flows from south to north through Central Siberia to the Arctic Ocean. The work, which was carried out by French, Russian and American scientists in the framework of the International Polar Year (IPY), is published in the journal Geophysical Research Letters.

The term greenhouse is used in conjunction with the phenomenon known as the greenhouse effect.

Energy from the sun drives the earth’s weather and climate, and heats the earth’s surface; In turn, the earth radiates energy back into space; Some atmospheric gases (water vapor, carbon dioxide, and other gases) trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse; These gases are therefore known as greenhouse gases; The greenhouse effect is the rise in temperature on Earth as certain gases in the atmosphere trap energy.

Six main gases considered to be contributing to global climate change are carbon dioxide (CO2), methane (CH4) (which is 20 times as potent a greenhouse gas as carbon dioxide) and nitrous oxide (N2O), plus three fluorinated industrial gases: hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF6). Water vapor is also considered a greenhouse gas.

Many of these greenhouse gases are actually life-enabling, for without them, heat would escape back into space and the Earth’s average temperature would be a lot colder. However, if the greenhouse effect becomes stronger, then more heat gets trapped than needed, and the Earth might become less habitable for humans, plants and animals.

The Tibetan plateau is heating up by 0.3°C each decade, more than twice the worldwide average, according to a new study from the Tibet Meteorological Bureau .

The findings, reported by the official Chinese news agency Xinhua, underscore a growing understanding that high elevations in tropical regions are experiencing dramatic temperature increases similar to those seen at the poles.

"Whether you are in the Himalayas, the Andes, or Africa, the temperature is rising highest at the highest elevations," says Lonnie Thompson, a glaciologist at the Ohio State University. "They are seeing an acceleration in temperature rise that is very consistent with the high-elevation glacial retreat we are seeing."

Over the last 50 years, temperatures in the Arctic and Antarctica have risen by 0.2°C and approximately 0.5°C per decade, respectively, according to data from the Intergovernmental Panel on Climate Change.

Pollution from various industries, the burning of fossil fuels, methane from farm animals, forest destruction, rotting/dead vegetation etc have led to an increased number of greenhouse gases in the atmosphere.

A scientist explained a fear that if the bogs dry out as they warm, the methane will oxidise and escape into the air as carbon dioxide. But if the bogs remain wet, as is the case in western Siberia today, then the methane will be released straight into the atmosphere. Methane is 20 times as potent a greenhouse gas as carbon dioxide.

Scientist fear that if international trade in its current form continues to expand with little regard for the environment, the transportation alone, of goods is thought to considerably contribute to global warming via emissions from planes, ships and other transportation vehicles.