M ODULE #2: C limate Change & Global Warming …Science & Sources of Greenhouse Gas (GHG) Emissions

Climate - the long-term average weather pattern of an area, including temperature, precipitation, and wind. Weather - the short term state of the atmosphere at a specific time and place, including the temperature, humidity, cloud coverage, precipitation, wind, etc. Climate Change - any long-term significant change in the average weather that a given region experiences. These changes can be caused by dynamic processes on Earth, external forces including variations in sunlight intensity, and more recently by human activities. Global warming - the increase in the average measured temperature of the Earth's near-surface atmosphere and oceans since the mid-twentieth century, and its projected continuation. Some useful definitions …

Is the Earth getting warmer? Is the Earths climate changing? Yes, it is constantly changing due to natural forcings (intensity of the sun, volcanic activity, etc.), but more recently as a result of human activites.

2006 warmest year ever The United States recorded its warmest year ever in °F above the 20th Century ave Source: NASA Source: Union of Concerned Scientists The Earths 20 Hottest Years on Record Yes.

Why is the Earth getting warmer ?

Thousands of peer-reviewed scientific research publications provide clear & convincing evidence for warming caused by humans (anthropogenic GHG emissions) Source: IPCC Report: Summary for Policy Makers, Climate Change 2001: The Scientific Basis Greenhouse Gas concentrations have increased dramatically since the industrial revolution. Prior to this, levels stayed relatively stable for thousands of years. Human activities are adding more GHGs to the atmosphere & boosting the Greenhouse Effect that we learned about in MODULE #1 in response to our actions! There is overwhelming evidence to show that our climate is changing Temperature is increasing as concentrations of CO 2 (& other GHGs) increase in Earths atmosphere U.S. Industrial Revolution begins

Graph courtesy of NASA. Data Source: Vostok ice core data/NOAA … CO 2 levels have now reached unprecedented highs, and continue to rise steadily every year …

H ow can we tell that the recent, rapid warming is caused by human (anthropogenic) activity rather than natural cycles? If scientists only consider Natural climate forcings (like solar & volcanic activity), then computer models tell them Earth shouldve been cooling down over the past 30 years (gray line)… but thats not what is happening in the real world (red line) But when GHG emissions from human activities are included in the computer models, the results match what scientists are seeing (temperature increasing)… so we are a key part of the equation!

Why is this problem uniquely caused by us? After all… After all… we humans live along with countless other species on planet Earth, and like all species … change our environment to a greater or lesser degree. … And change is inevitable. …BUT the rate (and magnitude) of change we have caused since the industrial revolution is much too great for the natural cycles to maintain a balance! As the American Geophysical Union recently concluded: "It is scientifically inconceivable that - after changing forests into cities, putting dust and soot into the atmosphere, putting millions of acres of desert into irrigated agriculture, and putting greenhouse gases into the atmosphere - humans have not altered the natural course of the climate system."

Lets take a look at the major sources Vermont of GHG emissions in Vermont… Can you guess which 2 sources below are responsible for nearly ¾ of Vermonts Greenhouse Gas Emissions? Transportation? Heating our homes and businesses? Agriculture? Industry? Landfills? Electricity generation / use?

Transportation Heating our homes & businesses Electricity Industrial processes Landfills / Waste Industrial fuel use Agriculture V ermonts Greenhouse Gas Emissions

How does Vermonts emissions profile compare to the entire United States?

Vermont United States GHG Emissions by Source Category (2000) How do these 2 pie charts differ? Can you think of reasons why Vermonts GHG emissions profile looks different?

Please go on to MODULE #3 to learn about how GHG emissions are changing things around the globe…