“Global warming is an average increase in the temperature of the atmosphere near the Earth’s surface and in the troposphere, which can contribute to changes in global climate patterns. Global warming can occur from a variety of causes, both natural and human induced. In common usage, “global warming” often refers to the warming that can occur as a result of increased emissions of greenhouse gases from human activities.”
The origins of the term global warming are traced back to a 1975 scientific paper titled, “Are we on the brink of a pronounced global warming?” It was later made famous, and “stop global warming” became the slogan of a generation, after the testimony of NASA climate scientist James Hansen in front of the U.S. Senate in 1988.
Global warming refers to a slight but noticeable increase in temperature at the planetary scale. The results are not just merely warmer weather, but an erratic climate that if left unchecked could cause pervasive natural disasters and species extinction.
The concern is that global warming is increasing. The greenhouse gas emissions that cause the warming trend are likely to continue into the future. The projection is that the warming will increase by six to ten degrees Fahrenheit by the end of the century.
While the international scientific community is in agreement about the reality of global warming, segments of the general public, particularly in the United States, are still skeptical.
Besides the development of clean technology, alternative energy sources, and carbon markets that will help reduce greenhouse gas emissions, education about the science behind global warming , the politics, and lifestyle choices that influence the trend will be crucial to curtailing future emissions. Teachers at all levels are now implementing climate change lessons into the general curriculum and college courses in environmental science, political studies, and environmental law are more widely offered.
Effects of global warming
The effects of global warming are the ecological and social changes caused by the rise in global temperatures. There is a scientific consensus that climate change is occurring, and that human activities are the primary driver. Evidence of climate change includes the instrumental temperature record, rising sea levels, and decreased snow cover in the Northern Hemisphere.According to the Intergovernmental Panel on Climate Change (IPCC), most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in human greenhouse gas concentrations.
Projections of future climate change suggest further global warming, sea level rise, and an increase in the frequency and severity of some extreme weather events. Parties to the United Nations Framework Convention on Climate Change (UNFCCC) have agreed to "stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system."
Our ever increasing addiction to electricity from coal burning power plants releases enormous amounts of carbon dioxide into the atmosphere. 40% of U.S. CO2 emissions come from electricity production, and burning coal accounts for 93% of emissions from the electric utility industry [EPA, pg. 10]. Every day, more electric gadgets flood the market, and without widespread alternative energy sources, we are highly dependent on burning coal for our personal and commercial electrical supply.
Our modern car culture and appetite for globally sourced goods is responsible for about 33% of emissions in the U.S. [EPA pg. 8] With our population growing at an alarming rate, the demand for more cars and consumer goods means that we are increasing the use of fossil fuels for transportation and manufacturing. Our consumption is outpacing our discoveries of ways to mitigate the effects, with no end in sight to our massive consumer culture.
Methane is another extremely potent greenhouse gas, ranking right behind CO2. When organic matter is broken down by bacteria under oxygen-starved conditions (anaerobic decomposition) as in rice paddies, methane is produced. The process also takes place in the intestines of herbivorous animals, and with the increase in the amount of concentrated livestock production, the levels of methane released into the atmosphere is increasing. Another source of methane is methane clathrate, a compound containing large amounts of methane trapped in the crystal structure of ice. As methane escapes from the Arctic seabed, the rate of global warming will increase significantly.
The use of forests for fuel (both wood and for charcoal) is one cause of deforestation, but in the first world, our appetite for wood and paper products, our consumption of livestock grazed on former forest land, and the use of tropical forest lands for commodities like palm oil plantations contributes to the mass deforestation of our world. Forests remove and store carbon dioxide from the atmosphere, and this deforestation releases large amounts of carbon, as well as reducing the amount of carbon capture on the planet.
In the last half of the 20th century, the use of chemical fertilizers (as opposed to the historical use of animal manure) has risen dramatically. The high rate of application of nitrogen-rich fertilizers has effects on the heat storage of cropland (nitrogen oxides have 300 times more heat-trapping capacity per unit of volume than carbon dioxide) and the run-off of excess fertilizers creates ‘dead-zones’ in our oceans. In addition to these effects, high nitrate levels in groundwater due to over-fertilization are cause for concern for human health.
Scientists predict an increase in sea levels worldwide due to the melting of two massive ice sheets in Antarctica and Greenland, especially on the East coast of the U.S. However, many nations around the world will experience the effects of rising sea levels, which could displace millions of people. One nation, the Maldives, is already looking for a new home, thanks to rising sea levels.
The severity of storms such as hurricanes and cyclones is increasing, and research published in Nature found:
“Scientists have come up with the firmest evidence so far that global warming will significantly increase the intensity of the most extreme storms worldwide. The maximum wind speeds of the strongest tropical cyclones have increased significantly since 1981, according to research published in Nature this week. And the upward trend, thought to be driven by rising ocean temperatures, is unlikely to stop at any time soon.”
According to recent research, there is a 90% chance that 3 billion people worldwide will have to choose between moving their families to milder climes and going hungry due to climate change within 100 years.
“Climate change is expected to have the most severe impact on water supplies. “Shortages in future are likely to threaten food production, reduce sanitation, hinder economic development and damage ecosystems. It causes more violent swings between floods and droughts.”" – Guardian: Global warming causes 300,000 deaths a year
According to research published in Nature, by 2050, rising temperatures could lead to the extinction of more than a million species. And because we can’t exist without a diverse population of species on Earth, this is scary news for humans.
This 6th mass extinction is really just a continuation of the holocene extinction which began at the end of the last ice age and has resulted in the extinction of nearly all of the Earth’s megafauna animals, largely as a result of human-expansion.
“Climate change now represents at least as great a threat to the number of species surviving on Earth as habitat-destruction and modification.” Chris Thomas, conservation biologist at the University of LeedsWidespread species loss and lists of endangered species just keep growing. This is a concerning matter on many fronts.
A report on coral reefs from WWF says that in a worst case scenario, coral populations will collapse by 2100 due to increased temperatures and ocean acidification. The ‘bleaching’ of corals from small but prolonged rises in sea temperature is a severe danger for ocean ecosystems, and many other species in the oceans rely on coral reefs for their survival.
“Despite the oceans’s immensity — 71 per cent of the Earth’s surface with an average depth of almost 4km (2½m) — there are indications that it is approaching its tipping point. For reefs, warming waters and acidification are closing in like a pair of jaws that threaten to make them the first global ecosystem to disappear.” – Times Online: 21st-century Noah’s Ark needed to save coral reefs from extinction
How Global Warming Works
The Greenhouse EffectGlobal warming is caused by an increase in the greenhouse effect. The greenhouse effect is not a bad thing by itself -- it's what allows Earth to stay warm enough for life to survive.
Although it's not a perfect analogy, you can think of the Earth sort of like your car sitting out in a parking lot on a sunny day. You've probably noticed that your car is always much hotter inside than the outside temperature if it's been sitting there for a while. The sun's rays enter through your car's windows. Some of the heat from the sun is absorbed by the seats, the dashboard and the carpeting and floor mats. When those objects release this heat, it doesn't all get out through the windows. Some is reflected back in. The heat radiated by the seats is a different wavelength than the light of the sun that made it through the windows in the first place. So a certain amount of energy is going in, and less energy is going out. The result is a gradual increase in the temperature inside your car.
The greenhouse effect is a little more complicated than your hot car. When the sun's rays hit the Earth's atmosphere and the surface of the Earth, approximately 70 percent of the energy stays on the planet, absorbed by land, oceans, plants and other things. The other 30 percent is reflected into space by clouds, snow fields and other reflective surfaces [Source: NASA]. But even the 70 percent that gets through doesn't stay on earth forever (otherwise the Earth would become a blazing fireball). The Earth's oceans and land masses eventually radiate heat back out. Some of this heat makes it into space. The rest of it ends up getting absorbed when it hits certain things in the atmosphere, such as carbon dioxide, methane gas and water vapor. After these components in our atmosphere absorb all this heat, they emit energy (also in the form of heat). The heat that doesn't make it out through Earth's atmosphere keeps the planet warmer than it is in outer space, because more energy is coming in through the atmosphere than is going out. This is all part of the greenhouse effect that keeps the Earth warm.