Global Warming Basics

About Global Warming

Global warming is termed to be the increase in the average temperature of Earth’s oceans and near surface air. This has been happening in the recent decades and is expected to continue. In fact the term global warming is said to be a specific example of climatic changes. In scientific and common terms, global warming refers to recent warming and also implies a human influence on the same. As per the United Nations Framework Convention on Climate Change (UNFCCC) the term “climate change” is used for the changes caused due to humans and “climate variability” is used for the changes caused due to other factors.

"Global warming refers to recent warming and also implies a human influence." 

Since the mid 1800’s there have been evidences of increase in temperature of the atmosphere and the oceans. The instrumental temperature record indicates the fluctuations of the temperature of oceans and the atmosphere. This record exists from 1850 onwards and it helps us to determine the changes of temperature evident from the mid 1800’s.

It is shown that the land and sea temperatures have increased by 1.4ºF (0.75ºC) during the period 1860 to 1900. But since 1979, land temperatures have started increasing faster than ocean temperatures. It has been evident that land temperatures have increased at 0.25ºC per decade whereas the ocean temperatures have increased by 0.13ºC per decade – almost double.

Readings indicate that the temperatures in the lower troposphere have increased between 0.22 and 0.4 ºF per decade since 1979. These readings are according to the satellite temperature measurements. It has also been known that the temperatures had been relatively stable over the one or two thousand years before the mid 1800’s.

But there were signs of regional fluctuations like Little Ice Age and Medieval Warm period before 1850. As per the estimates by NASA, 2005 was found to be the warmest year since 1850. As reliable instrumental measurements were available only in the late 1800’s, readings before that are almost unknown. The previous warmest year was 1998 and 1005 was found to be warmer than 1998 by a few hundredths of a degree.

"Recent study has shown that the increase of green house gases is a major cause for global warming."

Our climate system tends to vary through natural, internal processes. Also external forcing factors like volcanic emissions, solar activity, orbital forcing and green house gases are other factors that can affect climate system changes. Recent study has shown that the increase of green house gases is a major cause for global warming.

This conclusion is based on the study conducted over the last 50 years. Just adding carbon dioxide or methane to the atmosphere of earth will make the earth’s surface warmer. Green house gases are already present in the atmosphere which produces a greenhouse effect. This greenhouse effect is needed to keep the earth warm so that it is habitable. But excess greenhouse gases will result in warmer temperatures and that is exactly what is happening now.

Over the years there has been a debate concerning the net effect of the increased greenhouse gases. This debate is allowing for positive and negative feedback on the issue. An example of the feedback process is ice-albedo feedback. With increased carbon dioxide levels in the atmosphere, earth’s surface warms up and this leads to melting of the ice present near the poles. As ice melts, its place is taken up by water or land and both of them are less reflective than ice.

This means they will absorb more solar radiation and this causes more warming. As warming increases more ice will melt and this cycle keeps going on. The earth’s current climate has been thrown out of equilibrium due to excess greenhouse gases. But climate commitment studies do show us that even if the greenhouse gases are somehow maintained at the present levels, the earth would experience a further warming of about 1ºF.

If we don’t control the increase in greenhouse gases, then a lot of changes will occur on planet earth which would only make living on earth tougher. Hence the need to curtail emission of greenhouse gases has become a prime focus in recent years.

Nations around the world are now trying to implement actions to reduce the emission of greenhouse gases. Many strategies have been proposed to this effect. Some of the strategies to mitigate global warming are energy conservation, carbon taxes, using renewable energy, carbon offsets, carbon capture and storage, nanotechnology and environmental vegetarianism. A combination of these strategies would be beneficial in reducing the emission of greenhouse gases.

Kyoto Protocol is the world’s primary international agreement made for combating global warming. It is an amendment to the UNFCCC (United Nations Framework Convention on Climate Change). All countries that ratify this protocol have to commit themselves to reduce their carbon dioxide emissions and also the emissions of five other greenhouse gases.

If the countries maintain or increase emissions of these six gases, then they would have to engage themselves in emissions trading. The Kyoto Protocol exempts developing countries from meeting emission standards. India and China are developing countries and hence are not controlled by the Kyoto Protocol. But the irony is that China and India are the second and third largest emitters of carbon dioxide and other green house gases, next to the United States. Study done by the International Energy Agency predicts that China would exceed US emissions before the year 2010.

As global warming is a phenomenon occurring all over the world, countries have to unite and ensure that the emissions of greenhouse gases are controlled to ensure that the world we live in now would be worth living in for our children and grand children.