Climate is sometimes mistaken for the weather. But climate is different from the weather because it is measured over a long period of time, whereas weather can change from day to day, or from year to year. Climate change is the long-term alteration of temperature and typical weather patterns in a place. It may cause weather patterns to be less predictable. These unexpected weather patterns can make it difficult to maintain and grow crops in regions that depend on farming because expected temperature and rainfall levels can no longer be relied on. 

In polar regions, the warming global temperatures associated with climate change have meant ice sheets and glaciers are melting at an accelerated rate from season to season. The cause of current climate change is largely human activity, like burning fossil fuels, like natural gas, oil, and coal. Burning these materials releases what are called greenhouse gases into Earth’s atmosphere. There, these gases trap heat from the sun’s rays inside the atmosphere causing Earth’s average temperature to rise. 

The main reasons for the frequent climate changes are:

• Greenhouse gases- Concentrations of the key greenhouse gases have all increased since the Industrial Revolution due to human activities. Carbon dioxide, methane, and nitrous oxide concentrations are now more abundant in the earth’s atmosphere than at any time in the last 800,000 years. These greenhouse gas emissions have increased the greenhouse effect and caused the earth’s surface temperature to rise.
• Absorption of the sun’s energy- This effect is observed in heat islands, which are urban centers that are warmer than the surrounding, less populated areas. One reason that these areas are warmer is that buildings, pavement, and roofs tend to reflect very less sunlight than natural surfaces. 
• Variation in solar activity- Changes in the sun’s energy output can affect the intensity of the sunlight that reaches the earth’s surface. While these changes can influence the earth’s climate, solar variations have played little role in the climate changes observed in recent decades.
• Changes in earth’s orbit- The amount of summer sunshine on the Northern Hemisphere, which is affected by changes in the planet’s orbit, appears to be the primary cause of past cycles of ice ages, in which the earth has experienced long periods of cold temperatures (ice ages), as well as shorter interglacial periods (periods between ice ages) of relatively warmer temperatures.
• Volcanic activities- Some explosive volcano eruptions can throw particles (e.g., SO₂) into the upper atmosphere, where they can reflect enough sunlight back to space to cool the surface of the planet for several years. In addition, human activities emit more than 100 times as much carbon dioxide as volcanoes each year.
• Changes in carbon dioxide concentration- During warm interglacial periods, carbon dioxide levels were higher. During cool glacial periods, carbon dioxide levels were lower. The heating or cooling of the earth’s surface and oceans can cause changes in the natural sources and sinks of these gases, and thus change greenhouse gas concentrations in the atmosphere.

Climate change has a bad effect on our environment as well as some good intentions. We can conclude that the evidence that the concentrations of these gases in the atmosphere have increased and are still increasing rapidly, that climate change is occurring, and that most of the recent change is almost certainly due to emissions of greenhouse gases caused by human activities. Further climate change is inevitable; if emissions of greenhouse gases continue unabated, future changes will substantially exceed those that have occurred so far.

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