GLOBAL WARMING

Global Warming

Global Warming

Introduction

Global warming and climate variability occur as natural phenomena. Many factors can cause changes in the Earth's heat balance, and changes large enough to cause major episodes of warming and cooling have taken place many times in the Earth's past. One cause of change of great concern to scientists is the amount of heat-absorbing gas in the atmosphere (Oreskes, 2004). Carbon dioxide, water vapor, and several secondary gases absorb thermal infrared radiation released from the Earth's surface and the lower atmosphere.

Greenhouse effect is the phrase for when a planet's atmosphere and surface are warmed by the absorption and emission of infrared radiation of atmospheric gases. When absorption takes place, the gas molecules take on heat and air temperature rises. If the atmosphere is heavy with water vapor and carbon dioxide, then heat tends to be retained in roughly the same way as the glass of a greenhouse contains longwave infrared radiation and heat (Kok, 2008). Hence, greenhouse effect is commonly used to describe the role of carbon dioxide (CO2) and H2O vapor and various secondary gases in holding heat within the atmosphere.

Changing Ecosystems And Weather

Another possible effect associated with climate change is the potential danger it holds for marine ecosystems. As the sea-level rises, coupled with increased warming of the ocean waters, marine biodiversity will be further threatened by the myriad impacts on all marine ecosystems, from tropical coral reefs (especially in the Maldives), to polar ecosystems. Coral reefs are already under severe stress from human activities, and have experienced unprecedented increases in the extent of coral bleaching, emergent coral diseases, and widespread die-offs. Damages to coral reefs lead to depletion of important habitat for fish food (Fisher, 2006).

Changes in ocean temperatures, currents, and net productivity will affect the distribution, abundance, assemblages, and productivity of marine populations, with unpredictable consequences to marine ecosystems and fisheries. As the Earth's surface temperature warms, species may either migrate to a cooler, more suitable habitat, or die. Species that are particularly vulnerable to climate change effects include polar animals, such as seals, penguins, and polar bears, coral reefs, and many other endangered animal and plant species (Firor, 2006).

Climate change has the potential to alter the hydrologic cycle. In many regions of the world, global climate change will have significant effects on precipitation and évapotranspiration. Heavier rainfall could lead to flooding in many regions as warmer temperatures speed up the hydrologie cycle. Flood frequencies in some areas are likely to change. In northern latitudes and snowmelt-driven basins, floods may become more frequent, although the increase in flooding for any given climate scenario is uncertain and impacts will vary among basins (Baumert, 2007).

Over the past century, it is estimated that there has been a 5-10 percent increase in precipitation. Climate-induced changes in hydrology will affect the magnitude, frequency, and cost of extreme events, which have the greatest economic and social impact on humans. Flooding, the most costly and destructive natural disaster, is becoming a common and extreme event as a result of ...