Climate change is one of the greatest environmental, social and economic threats facing the planet. Climate means the generally prevailing weather in an area or region, averaged over a series of years. During the 20th century, the Earth’s average surface temperature rose by around 0.6º C. Global temperatures are predicted to rise by 1-6º C by 2100. Climate change is the result of global warming.

You've heard about global warming for years, but you may have only a vague sense of what it is. Global warming is caused by the greenhouse effect. Sunlight streams through the atmosphere, strikes Earth's surface, turns to heat, and then is radiated back toward outer space. But some of this heat is trapped by greenhouse gases in the atmosphere and reflected back to Earth. These warming gases, such as carbon dioxide (CO2), methane (CH4) and chlorofluorocarbons (CFCs), allow sunlight to pass in, but like the glass in a green­house, they block heat from escaping. As we pump more and more CO2 into the air, more heat is trapped.

Concentrations of greenhouse gases have increased grammatically. Carbon dioxide accounts for 55 percent of the greenhouse effect, CFCs account for 17 percent, methane for 15 percent and nitrous oxide for 5 percent. Higher concentrations of carbon dioxide are not natural at all (‘natural’ carbon dioxide forms only 0.03 percent of the atmosphere). The burning of fossil fuel in power plants, road and air transport, landfill sites and manufacturing processes all generate harmful emissions, which warm the Earth’s surface.

Rising temperatures mean rising sea levels as polar ice caps melt. Rising sea levels endanger coastal areas and small islands. Climate change makes the weather more unstable, bringing storms droughts, floods, hurricanes.

Some places, like the Midwest; could become so hot and dry that many crops couldn't grow there anymore. And all over the world, plants and animals may not be able to adapt quickly enough to the sudden changes in their habitats. Some species could even become extinct.

Global warming also has the potential affects plankton populations. Since these microscopic aquatic plants and animals now utilize huge amounts of CO2, even minor changes in their numbers could have a dramatic effect on the rate of warming.

Tropical diseases, such as malaria, will spread more widely in warmer, wetter climates.

The global warming will expand the incidence and distribution of many serious medical disorders. In some places, the number of deaths related to heat waves is projected to double by 2020. According to the World Health Organization, global warming is one of the largest public heals challenges for the 21st century. Heat stress, the disruption of ecosystems, the spread of infectious diseases, forced migrations, loss of freshwater supplies, storm-related flooding, increased air pollution, and the disruption of agriculture will all have vast effects on human health.

Developing a strategy to win global warming is a difficult task. Any attempt to stop climatic change must be global in scope and must persist for decades, even centuries. In one way or another, these efforts will affect the lives of nearly everyone on the planet. The threat of global warming is so grave that action should be taken immediately.

We have to switch to solar power and other alternative energy sources. In industries that continue to use fossil fuels should be taxed for the excessive carbon dioxide they release.

Individuals must do their part too, by taking public transport, instead of driving their car so much and by buying more energy-efficient appliances and cars. And we have to stop the burning of tropical rainforests by preserving these forests; we can reduce carbon dioxide emissions caused by the burning or save the trees and other vegetations that help absorb carbon dioxide.

It’s time to reduce pollution, to ban chlorofluorocarbons, and to stop destroying natural ecosystems.

The fight against climate change is a huge challenge, but it is essential to the future of our planet. Earth is millions of years old, much older than the humans. We know many of its secrets. Nevertheless there are many questions to study.