Global Warming

Here you will learn about Global Warming and its effects on the planet earth.

What is Global Warming?
Many kinds of pollution trap heat at the Earth’s surface, like a blanket. As pollution builds up, too much heat is being trapped. Global Warming is an increase in the average temperature in the Earth’s atmosphere, especially a sustained increase great enough to cause changes in the global climate. The present warming is generally attributed to an increase in the greenhouse effect, brought about by increased levels of greenhouse gases such as carbon dioxide, largely due to the effects of human industry and agriculture. Expected long-term effects of current global warming are rising sea levels, flooding, melting of polar ice caps and glaciers, fluctuations in temperature and precipitation, draught, heat waves, and forest fires. Also global warming can increase the strength of hurricanes making them even more dangerous. The heat is so strong it causes more tornadoes.

What are some of the effects?
The Earth’s temperature is rising and this affects us today. We are experiencing global climate changes right now. Sea level is rising due to melting glaciers posing a threat to coastal areas that are heavily populated and should expect flooding. There is about half as much ice floating in the Artic sea than there was 50 years ago, this will eventually lead to global changes in ocean currents. As temperatures get warmer, the water cycle speeds up more rain means more floods which have gotten three to six times worse than ten years ago. While other places will experience draughts because higher temperatures cause evaporation. Ecosystems are changing. We are loosing our coral reefs and polar bears are threatened with extinction. Migratory species may not be able to adjust fast enough to survive these changes. Species that will thrive in these rising temperatures like insects and rodents will multiple and increase in numbers causing health risks and disease.

Global Warming Causes
Global Warming occurs naturally but the devastating effects we are facing now are largely due to human activity especially in industrialized nations. Humans are adding excessive amounts of greenhouse gases into Earth’s atmosphere. Greenhouse gases such as carbon dioxide accumulate in the atmosphere and trap heat that normally would exit into outer space. Human use of fossil fuels is the main source of greenhouse gases. By driving cars, using electricity from coal-fired power plants, or heating our homes with oil or natural gas, we release carbon dioxide and other heat trapping gases into the atmosphere. Deforestation is another major source of greenhouse gases, because fewer trees means less carbon dioxide conversion to oxygen. During the 150 years of the industrial age, the atmospheric concentration of carbon dioxide has increased by 31 percent. Over the same period the level of atmospheric methane has risen by 151 percent, mostly from agricultural activities such as raising cows or growing rice. This increase in trapped heat changes the climate and alters weather patterns.

Kyoto Pact
The Kyoto Protocol is an international treaty whose aim is to stem global warming, signed in 1997 following negotiations within the U.N. In December 1997, around 180 nations signed a treaty in Kyoto Japan, in which 38 industrialized countries committed themselves to reducing emissions of the six greenhouse gases blamed for global warming. Countries who signed the pact committed to reduce greenhouse gases, or engage in emissions trading (an administrative approach used to control pollution by providing economic incentives for achieving reductions in the emissions of pollutants) if they maintain or increase emissions of these gases. The Kyoto protocol now covers more than 160 countries globally and over 55 percent of global greenhouse gas emissions. Disappointingly the U.S. under the Bush administration has refused to sign the Kyoto Pact Treaty. The U.S. is 4 percent of the world population but is responsible for 25 percent of the carbon dioxide emissions, consumes 25 percent of the world’s oil production, Americans use more than 50 million tons of paper annually consuming more than 850 million tress, every year U.S. industries release at least 2.4 pounds of chemicals into the atmosphere, and the list goes on and on.

Electricity and the Green choice
Burning fossil fuels like coal and oil supplies about 97 percent of America's electricity and is responsible for about 33 percent of the country's global warming pollution. U.S. households produce more than 21 percent of the country’s global warming pollution. Energy conscious families can reduce their emissions by up to two-thirds by making energy efficient choices. Because fossil fuel-based energy sources produce a lot of heat-trapping pollution, and renewable sources little or none, our energy choices are critical to stopping global warming. Energy efficiency is about using less energy to achieve the same results. Because energy cannot be created or destroyed using energy converts it into useful output and useless output, such as pollution. Sadly, many of our energy-hungry machines—including power plants—are not very efficient. One of the most common way of generating electricity, turbine power plants, coal is burned in a boiler to produce steam. The heat turns the turbine blades, which turn the shaft in the generator to produce electricity. Transforming coal to steam in this way is inefficient—it produces a little electricity and a lot of pollution. These are the sources of the electricity we use in the U.S. coal at 50 percent, nuclear at 20 percent, natural gas at 18 percent, oil at 3 percent and large scale hydro power at 6 percent. Today's electricity landscape is different. We have options.

What about the future?
Due to the enormous complexity of the atmosphere, the most useful tools for gauging future changes are 'climate models'. These are computer-based mathematical models which simulate, in three dimensions, the climate's behavior, its components and their interactions. Climate models are constantly improving based on both our understanding and the increase in computer power, though by definition, a computer model is a simplification and simulation of reality, meaning that it is an approximation of the climate system. The first step in any modeled projection of climate change is to first simulate the present climate and compare it to observations. If the model is considered to do a good job at representing modern climate, then certain parameters can be changed, such as the concentration of greenhouse gases, which helps us understand how the climate would change in response. Projections of future climate change therefore depend on how well the computer climate model simulates the climate and on our understanding of how forcing functions will change in the future.

Is the atmospheric/oceanic circulation changing?
A rather abrupt change in the El Niño - Southern Oscillation behavior occurred around 1976/77 and the new regime has persisted. There have been relatively more frequent and persistent El Niño episodes rather than the cool La Niñas. This behavior is highly unusual in the last 120 years (the period of instrumental record). Changes in precipitation over the tropical Pacific are related to this change in the El Niño - Southern Oscillation, which has also affected the pattern and magnitude of surface temperatures. However, it is unclear as to whether this apparent change in the ENSO cycle is caused by global warming.

Is sea level rising?
Global mean sea level has been rising at an average rate of 1 to 2 mm/year over the past 100 years, which is significantly larger than the rate averaged over the last several thousand years. Projected increase from 1990-2100 is anywhere from 0.09-0.88 meters, depending on which greenhouse gas scenario is used and many physical uncertainties in contributions to sea-level rise from a variety of frozen and unfrozen water sources.

Are El Niño’s related to Global Warming?
El Niño’s are not caused by global warming. Clear evidence exists from a variety of sources (including archaeological studies) that El Niño’s have been present for hundreds, and some indicators suggest maybe millions, of years. However, it has been hypothesized that warmer global sea surface temperatures can enhance the El Niño phenomenon, and it is also true that El Niño’s have been more frequent and intense in recent decades. Recent climate model results that simulate the 21st century with increased greenhouse gases suggest that El Niño-like sea surface temperature patterns in the tropical Pacific are likely to be more persistent


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