2 Questions Are global warming and climate change the same thing? What is the difference between climate and weather?What is the greenhouse effect?What is the most abundant greenhouse gas?Is climate change real?What evidence is there for climate change?Does the hole in the ozone layer cause climate change?
3 What’s the Difference? Global Climate Change Any significant change in measures of climate (temperature, precipitation, or wind) lasting for an extended period (decades or longer)Global WarmingAverage increase in the temperature of the atmosphere, which can contribute to changes in global climate patterns.
4 Weather vs. Climate Weather Climate Short-term (minutes to months) changes in the atmosphereClimateLong-term average pattern of weather in a particular areaTypically use 30 years of data
5 Greenhouse EffectEarth’s average temperature would be 0°F without the greenhouse effect compared to the average temperature of 60°F that we experience.
9 Carbon Dioxide Levels in Relation to Global Temperature
10 Key Indicators Sea level Land Ice Carbon Dioxide Concentration Timing of the seasonsGlobal Surface TemperatureAllergy seasonSnowfall/SnowpackArctic Sea Ice
11 Ragweed Pollen SeasonThese trends are strongly related to changes in the length of the frost-free season and the timing of the first fall frost.
12 Cherry Tree blossomPeak bloom date from main cherry trees in the Tidal Basin in Washington, D.C. Peak bloom date occurs when 70% of blossoms are in full bloom. Since 1921, peak bloom dates have shifted earlier by 5 days.
13 First FreezeFreeze dates have shifted later by a rate of half a day to one day per decade.
14 Bird MigrationTrends of northern movement are closely related to increasing winter temperature
15 Radiative ForcingGreenhouse gases produced by humans have caused overall warming influence on Earth’s climate since Carbon dioxide is by far the biggest contributor.
16 Evidence Sea Level Rise Global Temperature Rise Global sea level rose 17 cm (6.7 in) in the last centuryRate in the last decade nearly double that of the last centuryGlobal Temperature RiseEarth has warmed since 1880 with most of warming occurring since the 1970s20 warmest years occurred since 198110 warmest years occurred in the past 12 years
17 Evidence Warming Oceans Shrinking Ice Sheets Top 700 m (2,300 ft) of ocean showing warming of 0.302°F since 1969Shrinking Ice SheetsGreenland: lost km3 (36-60 cubic miles) of ice per year between 2002 and 2006Antarctica: lost 152 km3 (36 cubic miles) of ice between 2002 and 2005
18 Evidence Declining Arctic sea ice Glacial retreat Extent and thickness of Arctic sea ice has declined rapidly over last several decadesGlacial retreatRetreating almost everywhere around the world including Alps, Himalayas, Andes, Rockies, Alaska, and Africa
19 Evidence Extreme Events Ocean Acidification Number of record high temps increasing since 1950Number of record low temps decreasing since 1950Increasing numbers of intense rainfall eventsOcean AcidificationCO2 content of oceans increasing since 1750Currently increasing 2 billion tons per yearIncreased ocean acidity by about 30%
20 IPCC Intergovernmental Panel on Climate Change Group of scientists from around the world that review and assess information on climate changeClimate modelsand projections
21 Projections for North America Decreasing snowpackin the western mountains5-20% increase in yieldsof rain-fed agriculture insome regionsIncreased frequency, intensity and duration of heat waves
22 Projections for Latin America Gradual replacement of tropical forest by savannah in eastern AmazonRisk of significant biodiversity loss through species extinction in many tropical areasSignificant changes in water availability for human consumption, agriculture, and energy generation
23 Projections for Europe Increased risk of inlandflash floodsMore frequent coastalflooding and erosionGlacial retreat inmountainous areasReduced snow coverand winter tourismExtensive species lossesReductions of cropproductivity in South Europe
24 Projections for Africa By 2020, millionpeople are projected to beexposed to increasedwater stressYields from rain-fedagriculture could be reducedby up to 50% in some regionsby 2020Agricultural production,including access to food,may be severely compromised
25 Projections for AsiaFreshwater availability projected to decrease by 2050Coastal areas at risk for increased floodingDeath rate from disease associated with floods and droughts expected to rise
26 Wisconsin’s Climate 1950-2006 Average temperature increased 1.5°F Greatest amount of warming in winter and spring, especially NW WisconsinNighttime lows warming faster than daytime highs, especially in summerDecline in extremely cold winter nights, especially in NW WisconsinDate of last spring freeze occurring 6-20 days earlierDate of first fall freeze occurring 3-8 days laterGrowing season increased up to 4 weeksAnnual average precipitation increased 15% although parts of the North became drier
27 Wisconsin’s Future Climate Projections 4-9°F increase by mid-21st CenturyWarming most pronounced in winterFewer extremely cold winter nights and more hot summer daysProbability of greater than 3 in. rainstorms will increase during spring and fall
28 Projected change in the frequency of 2 inch precipitation events (days/decade) from 1980 to 2055 Projected change in the frequency of 90°F days per year from 1980 to 2055
29 Projected change in average winter temperature from 1980 to 2055 Projected change in annual temperature from 1980 to 2055