Climate Change 101 Margaret Mooney Cooperative Institute for Meteorological Satellite Studies University of Wisconsin-Madison
Weather is the condition of the atmosphere at a particular location and moment. Each day current weather conditions are given in local weather reports. Climate is the collective state of the atmosphere for a given place over a specified interval of time. There are three parts to this definition … “ Climate is what you expect, weather is what you get” Differences between Weather & Climate
Climate is the collective state of the atmosphere for a given place over a specified interval of time. There are three parts to this definition:
Location because climate can be defined for a globe, a continent, a region, or a city.
2. Time because climate must be defined over a specified interval. NOAA typically uses 30-year averages, whereas studying Earth’s history often involves averages of a century or longer.
3. Averages and extremes of variables such as temperature, precipitation, pressure & winds.
1) What does the acronym IPCC stand for? A - International Program on Climate and Culture B - International Panel on Climate and Culture C – Intergovernmental Panel on Climate Change D - International Panel on Climate Change E – Intergovernmental Program on Climate Change First, a short test …
2) Which of the following best defines greenhouse gas? A – Gas molecules that trap solar energy B – Gas molecules that scatter green light C – Heat-trapping gas molecules D – Gases emitted by greenhouse plants E – Gases emitted by greenhouse gardeners
3) What is the most abundant greenhouse gas? A – Water Vapor B - Methane C – Nitrous Oxide D – Carbon Dioxide E – Sulfur Dioxide
4) Which greenhouse gas is of most concern to climate scientist studying warming? A – Water Vapor B - Methane C – Nitrous Oxide D – Carbon Dioxide E – Sulfur Dioxide
5) What element constitutes the bulk of the mass in any single tree ? A - Chlorophyll B - Carbon C – Hydrogen D - Oxygen E – Carbon Dioxide
6) What was the first creature added to the endangered species list because of human-induced global warming? A – Carrier Pigeon B – Polar Bear C – Grizzly Bear D – Red Wolf E – White Sturgeon
7 ) TRUE or FALSE The Ozone Hole contributes to global warming. A - TRUE B - FALSE
A - TRUE B - FALSE 8 ) TRUE or FALSE Global Warming is accelerated by the melting of snow and ice cover surfaces.
9 ) Melting of Arctic snow & ice will likely result in rising sea levels. A - TRUE B - FALSE
10 ) Melting of Antarctic snow and ice will likely result in rising sea levels. A - TRUE B - FALSE
11 ) How long does it take for atmospheric C02 to disperse & quit trapping out-going thermal energy? A – 5 years B – 20 years C – 50 years D – 75 years E – 100 years
12 ) According to the 2007 IPCC report, how many inches could sea levels rise by 2100? A – 1 to 4 inches B – 4 to 7 inches C – 7 to 24 inches
Global Climate Change Global Temperature: Has increased by ~0.7°C over the last 100yr. The rate of increase is “accelerating”. Global data & graphs in this presentation are from 2007 IPCC report
Warming is Unequivocal Also, the Oceans are warming & becoming more acidic Rising atmospheric temperature Rising sea level Reductions in NH snow cover
Changes in sea ice don’t significantly affect sea level because this ice is already floating. Melting land ice (glaciers, ice caps, and ice sheets) increases sea level. Significant decreases in Arctic sea ice extent. A different world in the Arctic: present and future
Industrial revolution and the atmosphere The current concentrations of key greenhouse gases, and their rates of change, are unprecedented. Carbon dioxide Methane Nitrous Oxide Intergovernmental Panel on Climate Change 2007
How do CO 2 (and other gases) cause global warming?
The climate system is more complex than just CO 2 and radiation What about the feedbacks?
In a warming climate, water vapor plays a major role in a positive feedback loop that amplifies global climate change. ( H 2 0 responds to changes in climate, but it doesn’t drive climate change) One way to think about Climate Change is an intensification of the water cycle As the temperature of the atmosphere rises, more water is evaporated from ground storage (rivers, oceans, reservoirs, soil). Because the air is warmer, the relative humidity can be higher, and the atmosphere can 'hold' more water vapor. As a greenhouse gas, the higher concentration of water vapor is then able to absorb more thermal IR energy radiated from the Earth, thus further warming the atmosphere. The warmer atmosphere can then hold more water vapor and so on and so on. This is referred to as a 'positive feedback loop'.
"Extremes of precipitation are generally increasing because the planet is actually warming and more water is evaporating from the oceans, this extra water vapor in the atmosphere then enables rain and snow events to become more extensive and intense than they might otherwise be.“ Tom Karl, NOAA’s NCDC, June 2011. Extreme weather events have grown more frequent in the United States since 1980, partly due to climate change.
FEEDBACK SCENARIO: Advancing sea ice in cold ocean waters resulting in more ice-covered ocean water with a higher albedo that reflects more sunshine and cools the ocean further B – Negative Feedback Loop A – Positive Feedback Loop
FEEDBACK SCENARIO: A person who starts to perspire experiences evaportative cooling and a reduction in body temperature. B – Negative Feedback A – Positive Feedback
FEEDBACK SCENARIO: Economic panic sends a large volume of shareholders to the bank to withdraw their assets. Massive withdrawals accelerates panic and leads to more economic disruption. B – Negative Feedback A – Positive Feedback
FEEDBACK SCENARIO: Increased CO2 allows plants to grow faster & remove more CO2 from the atmosphere tending toward a state of equilibrium. B – Negative Feedback A – Positive Feedback
FEEDBACK SCENARIO: A warmer atmosphere that results in warmer soil in the arctic allows more CO2 and CH4 to be released from the tundra which traps more IR and warms the atmosphere further. B – Negative Feedback Loop A – Positive Feedback Loop
FEEDBACK SCENARIO: Melting sea ice amidst warm(er) ocean waters resulting in more ice-free ocean water with a lower albedo that reflects less sunshine and warms the ocean further. B – Negative Feedback Loop A – Positive Feedback Loop
Observed warming is consistent with observed changes: The duration of ice cover on lakes decreased by about 2 weeks over the 20th century in mid- and high latitudes of the Northern Hemisphere. There is a widespread retreat of nonpolar glaciers. Arctic sea-ice has thinned by 40% in recent decades (summer & autumn) And decreased in extent by 15% since the 1950s in spring and summer. Northern Hemisphere snow cover has decreased by 10% since the 1960s. The growing season has lengthened by about 1 to 4 days per decade during the last 40 years in the Northern Hemisphere, especially at higher latitudes. The global mean sea level has increased at an average annual rate of 1 to 2 mm during the 20th century .
Observations Are Humans Responsible? IPCC (1995): “ Balance of evidence suggests discernible human influence” IPCC (2001): “ Most of global warming of past 50 years likely (odds 2 out of 3) due to human activities” IPCC (2007): “ Most of global warming of past 50 years very likely (odds 9 out of 10) due to greenhouse gases” IPCC WG1 - 2007 (Intergovernmental Panel on Climate Change) Agung Chichon Pinatubo Natural forcings only Natural and human effects
Featuring information from the U.S. Global Change Research Program(USGCRP) 2009 report Global Climate Change Impacts in the United States Regional Climate Change
Increases in the average number of days with very heavy precipitation 1958 to 2007 From 1950 to 2006, Wisconsin as a whole became wetter, with a 10 percent increase in annual precipitation (3.1 inches) 2008 Lake Delton Dam failure due to heavy rains FLOODING Observed
www. climatewisconsin .org STORIES & INTERACTIVES from CLIMATE WISCONSIN
Cities and agriculture face increasing risks from a changing climate. Water supplies will become increasingly scarce, calling for trade-offs among competing uses, and potentially leading to conflict. Increasing temperature, drought, wildfire, and invasive species will accelerate transformation of the landscape. Increased frequency and altered timing of flooding will increase risks to people, ecosystems, and infrastructure. Unique tourism and recreation opportunities are likely to suffer. Southwest Key Issues