140 likes | 262 Views
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. . Some useful definitions ….
E N D
MODULE #2: Climate 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. Some useful definitions … 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.
Is the Earth’s climate changing? Is the Earth getting warmer? 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.
The United States recorded its warmest year ever in 2006 2.2°F above the 20th Century ave. 2007 2006 Source: NASA The Earth’s 20 Hottest Years on Record Yes. Source: Union of Concerned Scientists
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 U.S. Industrial Revolution begins • Temperature is increasing as concentrations of CO2 (& other GHGs) increase in Earth’s atmosphere Source: IPCC Report: Summary for Policy Makers, Climate Change 2001: The Scientific Basis There is overwhelming evidence to show that our climate is changing in response to our actions! • Thousands of peer-reviewed scientific research publications provide clear & convincing evidence for warming caused by humans (anthropogenic GHG emissions)
… CO2 levels have now reached unprecedented highs, and continue to rise steadily every year … Graph courtesy of NASA. Data Source: Vostok ice core data/NOAA
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! If scientists only consider Natural climate forcings (like solar & volcanic activity), then computer models tell them Earth should’ve been cooling down over the past 30 years (gray line)… but that’s not what is happening in the real world (red line) How can we tell that the recent, rapid warming is caused by human (anthropogenic) activity rather than natural cycles?
Why is this problem uniquely caused by us? 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."
Industry? Agriculture? Transportation? Heating ourhomes and businesses? Landfills? Electricity generation / use? Let’s take a look at the major sources of GHG emissions in Vermont… Can you guess which 2 sources below are responsible for nearly ¾ of Vermont’s Greenhouse Gas Emissions?
Transportation Heating our homes & businesses Agriculture Electricity Landfills / Waste Industrial fuel use Industrial processes Vermont’s Greenhouse Gas Emissions
How does Vermont’s “emissions profile” compare to the entire United States?
GHG Emissions by Source Category (2000) Vermont How do these 2 pie charts differ? Can you think of reasons why Vermont’s GHG emissions profile looks different? United States
Please go on to MODULE #3 to learn about how GHG emissions are changing things around the globe…