What's the Difference Between Climate Change and Global Warming?

When two terms have been used interchangeably for a long time, the difference between the two begins to blur. While many often consider climate change and global warming to be synonymous, there is in fact a vast difference between the two terms.

Before we understand the meanings of these terms, and how they differ, it is important to consider that the Earth's climate has undergone a vast change. This refers not only to the weather changes but also the changes in the water level, oceans, snow and ice.

Although natural factors are in a large way responsible for these changes, there are various human activities that have led to these variations as well. The release of the heat-trapping greenhouse gases into the atmosphere has led to a spike in the temperature, and caused a host of other changes in the Earth's climate.

The new climate changes are not only vastly unpredictable but also tend to pose a challenge to the entire ecosystem. So, is it climate change and the natural warming and cooling cycles that are responsible for melting of glaciers, the rise of the sea levels and the decrease in forest cover, or is this a direct result of global warming?

Climate Change: The sustained changes in the regional weather conditions over a long period. Climate change not only refers to temperature but also encompasses changes in the wind patterns, humidity, rainfall and severe weather events.

Global Warming: The term used to denote increasing temperature of the surface of the Earth and the lower atmosphere.

Before we understand climate change, it is important to take into account the meaning of weather and climate.

While weather refers to localized meteorological changes, climate change is defined as the sustained change in the average weather over a long period, possibly over two to three decades.

It incorporates the changes in air pressure, tropospheric temperature, sea surface temperature, land temperature, wind patterns, humidity, storms and precipitation over a period of time.

It is true that climate change has naturally occurred over a period due to factors like solar activity, dust in the atmosphere and volcanic activity. However, in the recent years, human factors have influenced climate change greatly.

To create a demarcation between the two terms, the United Nations Framework Convention on Climate Changes (UNFCCC) uses the term 'climate change' to indicate the changes in the composition of atmosphere and the resultant climate variations due to human activity, while the term 'climate variability' refers to the natural climate changes.

First used on August 8, 1975, by Wallace S. Broecker in the journal Science, the term global warming has gained prominence in recent years.

It refers to the increase in the Earth's surface temperature or the lower part of the atmospheric layer. While climate change is a broad term used for long-term weather changes, global warming refers to only one aspect of climate change, the temperature.

One of the probable cause of global warming could be the increase in the greenhouse gases in the atmosphere. Some of the common greenhouse gases in the atmosphere are carbon dioxide, methane, nitrous oxide and water vapor. Other greenhouse gases include fluorinated gases like hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride.

Greenhouse gases by themselves are not harmful. In fact, the presence of these gases are vital for sustenance of life on Earth as they prevent the heat from escaping from the Earth's atmosphere into space. This prevents the Earth's temperature from getting too cold.

However, with the increase in the greenhouse gases, especially carbon dioxide, due to factors like deforestation, fossil fuel burning and other human activities, the rise in temperature is faster. The gases trap the energy and prevent it from escaping from the lower atmosphere. This in turn increases the temperature.

There is massive debate over global warming and human responsibility for the same. The fluctuations in Earth's climate including the increase and decrease in temperatures has been observed for ages.

However, climate researchers in recent years have ascertained an increase in the Earth's temperature over the last 150 years. With the advent of the twentieth century, there has been an increase of 0.8 °C in the Earth's mean surface temperature, with around 0.2 to 0.3 °C (0.5 °F) temperature rise over the past 25 years.

The skepticism about global warming is because despite the concern raised by scientists, there has been an increase in the cold winters in certain places. What we fail to see is, warming is consistent with changes in the climate like increasing rain or snow.

This is because with increase in temperature, the precipitation increases and so there are changes in patterns of rainfall and snow.

This causes cooling in certain regions while others may experience more rainfall. Global warming is also consistent with extreme weather events, drying of the land and decrease in the ice mass of the glaciers.

The increase in global temperatures has had maximum effect on the warming of the upper ocean with average temperatures increasing by 0.3 °C (0.5 °F) over the past 25 years. As the water warms, the glaciers melt and the sea level rises which in turn may affect coastlines and small islands.

This has also led to the increasing acidification of the ocean which disrupts the oceanic ecosystem. Other related problems include increase in diseases and pests and agricultural failure.

So, can we safely say that global warming caused by the increasing greenhouse gases in the atmosphere is what causes climate change? This would be more or less correct because the extent of the term global warming is limited. It fails to explain the long-term consequences of the phenomena.

Climate change on the other hand is a broad term which encompasses not only global warming but also the related weather changes over the long-run. This is also the reason why majority of the scientists prefer to use climate change to describe the complex effect that human activity has had on the climate.

Irrespective of the term we use, it is important to note the impact that the continued emission of greenhouse gases and warming of the Earth would have. Assessment and efforts to reduce their effect is necessary for the ecosystem and human well-being.