The atmospheric concentrations of several greenhouse gases are rising as a result of human activities on earth. Carbon Dioxide, one of the most important industrial gases today, is released in the atmosphere largely by burning of fossil fuels like coal, natural gas and oil. Its concentration in the atmosphere is known have increased by 30% over the past centuries. Like CO2 other greenhouse gases such as methane, nitrous oxide have been increasing as well.

With the pace with which human activity on earth continues to grow climate scientists believe that the global average temperature will continue to rise. According to a research report released by IPCC (Intergovernmental Panel on Climate Change) by the end of the next century earth may warm by 1.8ºF to 6.3ºF (1°-3.5°C) easily making it warmer than any time since the evolution of humans and adding to that and all of the 10 warmest years on record have occurred in the last 15 years. The record year for climate so far has been 1998, when melting snow killed 4,000 people in China, 1,400 in India and 1,00 in Pakistan. Typhoons killed 500 in the Philippines, and monsoons killed 1,300 in Bangladesh. Last year torrential rain in Venezuela caused floods that killed 30,000 people, and this year thousands have died in flooding in Mozambique. Global Warming may have already killed 100,000 people in the past three years and threatens to lead to mass migration, disease, poverty and even war. Famous Historian David Keys says "There have always been severe weather events, but the number and severity has increased in recent years." He adds that exceptionally severe weather events have claimed between 50,000 and 100,000 lives since 1997. In addition, up to 300 million people have been displaced and made homeless.

Figure: Global Rise in Temperature

Such a global rise in temperature would result in considerable climatic changes on earth. This in turn would have devastating effects on society and ecosystems. Global Warming is occurring right now too! Even within the next 20 years, different regions of the world will likely see longer droughts, more flooding and more frequent extreme weather changes. Increased global warming will also affect natural habitats and water resources. Human well-being, including business and economic development, could well be at risk. The most serious impacts will most likely include human health, agriculture, and natural habitats. Its impacts can be broken down into the following:

Human Health

Human health will be severely at risk if global warming continues to grow. Scientists say that warmer weather will create ideal conditions for the insects and rodents that carry malarial and several other viruses. Heat related illnesses and deaths could increase because of hotter weather and longer heat waves. Rising temperatures could also significantly reduce air quality. This would create ideal conditions for the increase in frequency and severity of several respiratory ailments. Diseases that are spread by mosquitoes and other insects could become more prevalent if warmer temperatures enabled those insects to become established.

According to the IPCC, "Climate change is likely to have wide-ranging and mostly adverse impacts on human health with significant loss of life." Children, the elderly and the poor will be most vulnerable to the human health effects from global warming. The developing world will suffer much more than the industrialized world.

Agriculture

Agriculture depends very heavily on a stable climate. Crops are very precise about the soil, moisture, temperature, carbon dioxide and other materials they require. With global warming occurring, the patterns of agricultural production are certainly going to change. Global Warming will also lead to more intense weather conditions like heavy rains and floods resulting in more and more crop destruction. These changing rainfall patterns could also shift crop diseases and pests and create water shortages in some areas.

In short, Climate change will most likely bring regional shifts in production and increased demand for irrigation; if extreme weather events were to become more frequent, the outlook for agriculture could become much less favorable.

Extreme Weather Changes

• more hurricanes, floods and droughts
  

• longer spells of intense heat or rain on different regions of earth
  

• rising sea levels as the polar caps will melt. Sea level is already on an all time high since its recording began.

Natural Habitats

In the past the environment has always adopted the ongoing climatic changes on the planet. But whenever sudden changes have taken place the effects have been devastating, and same is the case with global warming. It is occurring right now and at a quick pace. The fact that earth's overall temperature for every region is going to rise considerably, it is very likely that the forest and plant population of the area will become extinct and in some places totally finish. Forest fires are likely to become more frequent and severe if the soil becomes dry. The potential impacts of climate change on forest and wildlife are poorly understood. If habitats simply shift to cooler areas, many forms of wildlife could potentially adapt to global warming, just as they have adapted to the changes in climate that have occurred over the last several million years. Unlike previous climatic shifts, however, roads, development, and other modifications to the natural environment may block the migration routes. Nature reserves, often established to protect particular species, may no longer be located in a climate hospitable to that species.

Depletion of Ozone Layer

Scientists believe that rising Global Warming will result in a weaker ozone layer. The Ozone layer protects all life on earth from the harmful Ultraviolet radiations coming from the Sun. The Ozone filters the radiations which could cause skin cancer and various other diseases. This Ozone layer has been depleting many years now. The world has been alarmed by the detection of holes in the ozone layer over Antarctica. The holes are places where the ozone is absent. Scientists say that current hole in ozone over Antarctica is two and a half times the size of Europe and is still growing. Steps are now being taken at international level to prevent preparation and use of the harmful chemical compounds that contribute adversely to the climatic changes. Saving the life preserving ozone layer is one of the most important problems facing the environment scientists today. A further depletion in the ozone could result in extinction of all forms of life.