Global warming refers to the increase in average temperature near the earth's surface and in its oceans. Climate change is another term used interchangeably with global warming. However, climate change may encompass other changes in climate besides increases in temperature.
In the past century the average air temperature near the earth's surface has increased by around 1.4 degrees Fahrenheit. Various models have attempted to predict how these temperature changes may impact on the future. They variously predict increases from 2.5 to 10.4 degrees Fahrenheit. Most scientists agree that temperatures are likely to continue increasing. However, they do not agree nearly as much when it comes to predicting the magnitude of the increase.
So what actually causes the increased temperatures?
The earth's temperature is affected by many factors such as:
The earth's orbit - The tilt of the earth axis as it revolves around the sun influences the amount of sunlight reaching earth. Therefore changes in the earth's orbit affects its surface temperature.
Changes in intensity of heat emitted by the sun can also affect temperature on earth.
Volcanic activity - Lava, ash, dust and hot gases from volcanic eruptions can create volcanic aerosols which reflect heat away from the earth's surface and result in cooler temperatures. For instance 1816 is said to have been a year without a summer - widely believed to have been a result of the eruption of the Tambora volcano in Indonesia in the previous year. On the other hand, volcanoes also emit huge quantities of Carbon Dioxide, which tend to have the opposite effect and could lead to higher temperatures.
The causes listed above have existed for a very long time. However, since the Industrial Revolution and especially since 1900 another cause has taken precedence. Increased use of fossil fuels and the resulting emissions of carbon dioxide have caused massive increases in greenhouse gases. This has led to increased temperatures through the greenhouse effect.
What is the greenhouse effect and how does it impact on surface temperature?
The earth receives heat from the sun. The earth loses heat by reflecting it back into the atmosphere. The atmosphere contains a mixture of gases that trap heat and keep the earth's surface warm. This is similar to the mechanism that keeps the inside of a garden greenhouse warmer than the outside. These greenhouse gases are vital for life on earth. If they did not exist it is likely that earth would be too cold to sustain life. However, too much of a good thing can have bad consequences. As a result of our energy intensive lifestyles and the burning of vast quantities of fossil fuels the levels of greenhouse gases have been increasing rapidly which magnifies the greenhouse effect and traps more and more heat close to the earth's surface. Greenhouse gases are primarily Water vapor, Carbon Dioxide, Methane, Nitrous Oxide and Ozone.
What are the consequences of global warming?
As the earth becomes hotter all year round the incidence of droughts and wildfires will increase. There is already evidence of this in effect. Many US cities have recorded their hottest ever temperatures within the last 3 decades and vast areas worldwide are drought affected and subject to horrific wildfires.
Warmer water in the oceans feeds energy into more and more powerful storms and dangerous hurricanes. The warmer seas also result in melting of glaciers and ice caps that in turn cause higher sea levels and flooding of coastal communities. Many small island nations in the Pacific face the prospect of becoming totally submerged in the very near future.
Spread of insect borne diseases such as malaria- Areas which were previously inhospitable to hosts of these diseases such as mosquitoes become breeding grounds as temperatures change. This could lead to the spread of tropical diseases to more temperate areas.
Changes in climate will also push many species of animals and plants to extinction as they struggle to survive in their changing environments.
As with most debates there are the naysayers, predominant among them is the American Association of Petroleum Geologists, the only scientific society that rejects the conclusion that global warming is a threat.
However, if the 30 other scientific societies and academies who support the findings of global warming are to be believed, the consequences are obviously serious if not downright frightening! So what's being done to control it?
Governments around the world have undertaken programs to cut back the level of emissions of greenhouse gases. For instance in the US the government has a strategy in place to reduce emissions by 18% over the 10 year period 2002 to 2012. To this end the Environmental Protection Agency has implemented many initiatives to encourage the reduction of emissions by various industries and other stakeholders.
However, this is not a responsibility that rests exclusively with government or regulatory bodies. Every individual contributes to greenhouse gas emissions and therefore has an obligation to help cut back.
What can an individual do to help?
The list of ways to cut back on emissions is probably as long as the many ways that energy is expended but there are several obvious and relatively easy ways to achieve improvements:
In the US about half of greenhouse gas emissions come from power plants while about a third comes from transportation. Any activity that cuts back on power usage or reduced use of transportation would have a positive impact.
Using energy efficient electrical appliances including compact fluorescent lights instead of traditional globes would help. In the US energy efficient appliances in more than 50 categories can be identified by their "Energy Star" rating.
Similarly using more fuel-efficient cars or perhaps even reducing the use of cars and opting for more "green" transport methods such a bicycles, using public transport or even walking could help.
Using vehicles that run on renewable fuel sources such as E85 (A fuel containing 85% Ethanol) or bio-diesel.
Ensuring that tire pressures are at appropriate levels and your vehicles engine is tuned to manufacturers specifications would also help reduce fuel consumption.
Switching to greener sources of energy. Using solar power directly where the technology permits. Where there is no option but to use electricity or other traditional energy sources then it may be possible to make this purchase from a supplier who uses green, non fossil fuel sources to produce it.
Planting trees to offset the effects of the carbon dioxide emissions created in the production of the energy and other products one consumes is another alternative. It isn't necessary to do this oneself. Around the world there are organizations that are gearing up to do this on behalf of the many millions of concerned consumers. So for instance a power company could estimate the greenhouse gases emitted to produce a kilowatt-hour of electricity and then allow its customers an opportunity to pay to offset these emissions and become "carbon neutral".
Other ways of conserving energy would include cutting back on waste thereby saving on the energy that would be expended on replacement of the wasted item - Recycle and reuse whenever possible.
Saving on water consumption - A huge amount of energy is spent on purifying water for consumption so cutting back on water waste will help considerably.
Ensuring you have efficient insulation and that cooling and heating appliances are cleaned and primed to work efficiently.
Although individual actions may seem trivial their cumulative impact worldwide can be literally life changing. It is clear that much can be done at an individual level to control global warming. Although they cannot agree on the magnitude of global warming the overwhelming majority of the scientific community agree that it is a very real problem. The time for action is now! The consequences of doing nothing are just too frightening to comprehend!