Climate Change: an Emerging Issue in Global Environmental Health
Climate change is one of the emerging issues for global environment. It may be defined as the long-term change in average weather conditions, including temperature, precipitation and wind. This is already apparent as evidenced by higher temperatures, rising sea levels, increased ocean acidity and ice melt. Global surface temperatures, alone, have increased by roughly 0.74 °C (1.33 °F) between the start and the end of the 20th century. Natural causes alone cannot explain all of these changes. Most of the warming of the past half century has been caused by human emissions of greenhouse gases. This gases act like a blanket or glass roof around the earth, trapping in heat that would otherwise escape to space – this is commonly referred to as the “greenhouse effect”. From the end of the last Ice Age about 10,000 years ago to the end of the 18th century, the levels of greenhouse gases in the atmosphere remained fairly constant and at a level sufficient to sustain life as we know it today. Since the Industrial Revolution 200 years ago, mankind has been releasing unprecedented amounts of greenhouse gases into the atmosphere, which trap more heat, amplifying the natural greenhouse effect. Carbon dioxide (CO2) is the most significant greenhouse gas released by human activities and is emitted mostly from the burning of fossil fuels like coal, oil and natural gas. Other greenhouse gases include methane and nitrous oxide. Without effective action to halt the rise and then reduce the levels of greenhouse gases released by human activity, countries worldwide and their citizens face significant changes in food and water resources, health and living standards as they are forced to adapt to a changing climate. It is predicted that society will face disruption from extreme weather, with more frequent storms and flooding, more severe droughts and heat waves, which will result in a loss of agricultural land and biodiversity. In many regions agriculture will be adversely affected by