The Carbon Cycle Background information

What is the carbon cycle? 0 The carbon cycle is the natural flow of carbon through the earth. 0 It is largely influenced by plants, animals, and weather. 0 A little bit of carbon -relatively speaking- in the atmosphere is good to have because it keeps our planet from freezing over.

Copy this into your notes! OILNatural Gas

What is earth’s AGT? 0 Earth’s AGT (average global temperature) has varied over its 4.5 billion year existence. 0 Sometimes the AGT has been VERY LOW (an ice ball) and other times, the AGT has been VERY HIGH (no ice). 0 Ice ages occur every 150,000 years and the temperature is reduced about 12 degrees Celsius. 0 Interglacial periods result in warmer temperatures with a rise of only 4 degrees Celsius. 0 Such a small change in temperature can result in vastly different environmental conditions.

Carbon influences our AGT 0 About 200 years ago, CO 2 emissions started to influence earth’s AGT! 0 CO 2 emissions that are most prevalent are CONG: 0 COAL 0 OIL 0 NATURAL GAS 0 CONG will raise earth’s AGT by 6 degrees Celsius by 2100! 0 If that happens, we will not recognize our home anymore: 0 Less water, more diseases and famines, 50% fewer species, and hardly any capacity to support human life as we know it!

Why does CONG affect our AGT? 0 All fossil fuels are made of carbon (C) and hydrogen (H) and when they are burned, they release a HUGE amount of energy. 0 The energy is helpful for us, but it comes with a big price tag. 0 When fuels are burned, the C and H split and the C bonds with O 2 in the atmosphere… which creates CO 2 (carbon dioxide). 0 A little bit of CO 2 is actually good because it keeps our planet from freezing solid, however, we have raised CO 2 levels from 280ppm to 392ppm in just a few hundred years.

If we continue to burn carbon at our current rate, we will reach 450ppm of CO 2 in just 30 years. This means that the AGT will increase by 2 degrees Celsius.

If the temperature rises, more carbon will be released into the atmosphere. If more carbon is released into the atmosphere, the temperature will rise and begin a runaway climate change issue.

What is a carbon sink? 0 Humans emit about 9 gigatons of carbon each year (2.2 trillion pounds…the weight of ALL humanity is just 1 trillion pounds). 0 Oceans (40%) and land plants (30%) are carbon sinks, because they take up most of the CO 2 that would otherwise be released into the atmosphere. 0 Our carbon sinks are becoming less and less capable of soaking up CO 2 because of the rising temperatures. 0 It’s a horrible feedback loop!!!

Hope for the future? 0 The 9 GT of CO 2 we emit each year is expected to rise to 16 GT by 2060 due to overpopulation. 0 However, our carbon sinks can only hold 4GT of CO 2 … 0 SO, we need to cut our CO 2 emissions by 12GT in the next 40 years or so to avoid the runaway climate change that would be the result. 0 There is NO WAY to reduce 12GT of our carbon emissions in one year, but some scientists have come up with a way to reduce our CO 2 emissions by 1GT every year… Pacala and Socolow.

Sustainability Wedges

How do I know how much I’m contributing to earth’s AGT? 0 Find out what your ecological footprint is on earthday.org 0 Answer slip and turn in. 0 We will discuss global actions tomorrow with Pacala and Socolow’s wedges! 0