Global warming

Global warming is the name given by scientists for the gradual increase in temperature of the Earth's surface that has worsened since the industrial revolution.


Over the past two decades the effect has become more marked. Considerable **evidence** exists that most of this warming has been caused by human activities... that's to say we have altered the chemical composition of the atmosphere through a build up of greenhouse gases – primarily carbon dioxide, methane, and nitrous oxide.
What if we do nothing? Rising global temperatures will cause sea level to rise and alter local climate conditions, affecting forests, crop yields, and water supplies. It may also affect human health, animals, and many types of ecosystems. Deserts may expand and some of our countryside may be permanently altered.

What will happen in the future if we do nothing?

· Climate model simulations predict an increase in average surface air temperature of about 2.5°C by the year 2100 (Kattenberg et al., 1996).
· The likelihood of "killer" heat waves during the warm season will increase (Karl et al., 1997)
· The IPCC Second Assessment Report estimates that sea-level will rise by approximately 49 cm over the next 100 years, with a range of uncertainty of 20-86 cm.
· Sea-level rise will lead to increased coastal flooding through direct inundation and an increase in the base for storm surges, allowing flooding of larger areas and higher elevations.
· Further melting of the Arctic Ice Caps (at the current rate) could be sufficient to turn off the ocean currents that drive the Gulf Stream, which keeps Britain up to 6°C warmer than it would otherwise be.

What can I do?

You have to go to work and we all like being consumers - but there are many ways you can help. Firstly, you need to recognise how you personally impact global warming. Carbon Footprint will show you how to minimise your impact - starting today - and show you how to make the right product choices in the future



The greenhouse effect

The atmosphere has a natural supply of "greenhouse gases." They capture heat and keep the surface of the Earth warm enough for us to live on. Without the greenhouse effect, the planet would be an uninhabitable, frozen wasteland.
Before the Industrial Revolution, the amount of carbon dioxide (CO2) and other greenhouse gases released into the atmosphere was in a rough balance with what could be stored on Earth. Natural emissions of heat-trapping gases matched what could be absorbed in natural sinks. For example, plants take in CO2 when they grow in spring and summer, and release it back to the atmosphere when they decay and die in fall and winter.

Too much greenhouse effect

Industry took off in the mid-1700s, and people started emitting large amounts of greenhouse gases. Fossil fuels were burned more and more to run our cars, trucks, factories, planes and power plants, adding to the natural supply of greenhouse gases. The gases—which can stay in the atmosphere for at least fifty years and up to centuries—are building up beyond the Earth's capacity to remove them and, in effect, creating an extra-thick heat blanket around the Earth.
The result is that the globe has heated up by about one degree Fahrenheit over the past century—and it has heated up more intensely over the past two decades.
If one degree doesn't sound like a lot, consider this: the difference in global average temperatures between modern times and the last ice age—when much of Canada and the northern U.S. were covered with thick ice sheets—was only about 9 degrees Fahrenheit. So in fact one degree is very significant—especially since the unnatural warming will continue as long as we keep putting extra greenhouse gases in the atmosphere.

How much is too much?

Already, people have increased the amount of CO2, the chief global warming pollutant, in the atmosphere to 31 percent above pre-industrial levels. There is more CO2 in the atmosphere now than at any time in the last 650,000 years. Studies of the Earth’s climate history show that even small changes in CO2 levels generally have come with significant shifts in the global average temperature.
Scientists expect that, in the absence of effective policies to reduce greenhouse gas pollution, the global average temperature will increase another 2.0 degrees Fahrenheit to 11.5 degrees Fahrenheit by 2100.
Even if the temperature change is at the small end of the predictions, the alterations to the climate are expected to be serious: more intense storms, more pronounced droughts, coastal areas more severely eroded by rising seas. At the high end of the predictions, the world could face abrupt, catastrophic and irreversible consequences. .

The science is clear

Scientists are no longer debating the basic facts of climate change. In February 2007, the thousands of scientific experts collectively known as the Intergovernmental Panel on Climate Change (IPCC) concluded that there is greater than 90 percent likelihood that people are causing global warming. (IPCC, 2007)

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