Heat from the Sun supplies our planet with much-needed warmth. But over the past 150 years more heat has been retained by Earth as the amount of heat-trapping greenhouse gases in the atmosphere has grown
Click on image for full size
Courtesy of USGS Astrogeology Research Program
What Controls the Climate?
Some of the factors that have an affect on climate, like volcanic eruptions and changes in the amount of solar energy, are natural. Others, like the addition of greenhouse gases to the atmosphere, are caused by humans. Some of the main ones are listed below.
The Sun Affects Climate
Climate can change if there is a change in the amount of solar energy that gets to Earth. Changes to the cycle of solar activity, called the 11-year solar cycle, can cause a small impact on climate, too small to be the cause of recent climate change. Over thousands of years, changes in the way Earth orbits the Sun can cause large changes in climate.
Volcanic Eruptions Affect Climate
When volcanoes erupt they spew more than hot red lava and ash. They release tiny particles made of sulfur dioxide into the atmosphere too. These particles get into the stratosphere and reflect solar radiation back out to space. This causes cooling. The cooling is temporary, lasting usually a year or two.
Greenhouse Gases Affect Climate
Greenhouse gases have a strong affect on climate. These gases trap heat through a process called the greenhouse effect. While greenhouse gases are a natural part of the atmosphere, the amount has increased over the past 150 years as fossil fuels have been burned and the amount of forests, which naturally take up the greenhouse gas carbon dioxide during photosynthesis, has shrunk.
Snow and Ice Affect Climate
Because the snow and ice of the cryosphere are light in color, they have a large albedo – the ability to reflect most solar radiation back out to space. When snow and ice melt as Earth’s climate warms, less energy is reflected and this causes even more warming.
There are also other aspects of our planet that have an impact on climate too. Scientists are studying the impact of clouds and the impact of aerosols on climate. Scientist are studying the oceans too because melting Arctic sea ice could change ocean circulation, causing regional climate to change.
Shop Windows to the Universe Science Store!
The Winter 2009 issue of The Earth Scientist
, focuses on Earth System science, including articles on student inquiry, differentiated instruction, geomorphic concepts, the rock cycle, and much more!
You might also be interested in:
The climate where you live is called regional climate. It is the average weather in a place over more than thirty years. To describe the regional climate of a place, people often tell what the temperatures...more
For more than 100 years, scientists have wondered if cycles on the Sun and changes of the energy received at Earth because of those cycles affect weather or global climate on Earth. It is now thought that...more
Ash is made of millions of tiny fragments of rock and glass formed during a volcanic eruption. Volcanic ash particles are less than 2 mm in size and can be much smaller. Volcanic ash forms in several ways...more
When you look up at the sky, you are looking at more than just air. There are also billions of tiny bits of solid and liquid floating in the atmosphere. Those tiny floating particles are called aerosols...more
Even though only a tiny amount of the gases in Earth’s atmosphere are greenhouse gases, they have a huge effect on climate. There are several different types of greenhouse gases. The major ones are carbon...more
Energy from the Sun that makes its way to the Earth’s surface can have trouble finding its way back out to space. This is because of a natural process called the greenhouse effect. Without the greenhouse...more
Carbon dioxide (CO2) is a kind of gas. There isn't that much carbon dioxide in Earth's atmosphere, but it is still very important. Carbon dioxide is a greenhouse gas. That means it helps trap heat coming...more