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Medicine LibreTexts

14.1: The Importance of a Healthy Planet

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    13419
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    What is Climate Change?

    Climate change is the term used to describe the Earth’s changing climate. Researchers are able to estimate climate changes that occurred in the last 650,000 years by measuring the CO2 in ice cores. The amount of CO2 in our atmosphere is directly related to temperature; the more CO2 the higher the temperature, the lower the CO2 the lower the temperature.

    The term Ice Age has been used to describe seven cyclical periods in the last 650,000 years when the planet cooled dramatically. The cyclical cooling and warming of the past was prior to human civilization and was attributed to slight changes of the Earth’s rotation that changed the amount of solar radiation the planet received.

    Using the term climate change today, in modern times, reflects the change that is occurring most likely due to the human population. Prior to 1950, the atmospheric level of CO2 had never reached 300 parts per million and the current level today is about 400 parts per million. During the Ice Ages the level of CO2 was about 180 parts per million

    Global Warming

    The sun provides solar radiation to our planet. When the Sun’s solar rays hit our planet the solar radiation turns to heat. CO2 is one of several gases in our atmosphere that block heat from escaping the planet. When there is more CO2 there is more heat trapped. The trapping of heat has been termed Global Warming.

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    To help you understand how the sun’s rays turn to heat and then get trapped in by greenhouse gases, just imagine stepping into a greenhouse. The temperature inside and outside of a greenhouse can be very different. Outside of a greenhouse you can feel the heat from the sun’s rays, but the heat can escape to the atmosphere. Inside the greenhouse, the sun’s rays are turned to heat and the heat is trapped by the greenhouse. The way the greenhouse traps heat is similar to how the greenhouses gases, such as CO2 trap heat and increase the temperature of the planet.

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    Evidence of Rapid Climate Change:

    • Global temperature rise

      • The planet’s temperature has risen about 2 degrees fahrenheit since the late 19th century. 16 of the 17 warmest years ever recorded have occurred since 2001.

    • Warming oceans

      • Oceans absorb the heat and thus our oceans have increased in temperature by about .302 degree fahrenheit since 1969.

    • Shrinking ice sheets

      • Both Greenland and the Antarctica are losing Ice. Greenland lost 36-60 cubic miles of ice per year from 2002-2006 and Antarctica lost about 36 cubic miles of ice from 2002-2005.

    • Glacial retreat

      • Glaciers are disappearing around the world.

    • Decreased snow cover

      • Snow cover has decreased in the northern hemisphere over the past 50 years and snow is melting earlier.

    • Sea level rise

      • Sea level has risen about 8 inches in the last 100 years. The last 20 years sea level has risen double the amount from the last century.

    • Declining arctic sea ice

      • Arctic sea ice has decreased in size and depth.

    • Extreme events

      • Extreme weather events have risen.

    • Ocean acidification

      • Ocean waters have become more acidic due to more CO2

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