Climate Change Climate Change

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?

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 Warming Average increase in the temperature of the atmosphere, which can contribute to changes in global climate patterns.

Weather vs. Climate Weather Climate Short-term (minutes to months) changes in the atmosphere Climate Long-term average pattern of weather in a particular area Typically use 30 years of data

Greenhouse Effect Earth’s average temperature would be 0°F without the greenhouse effect compared to the average temperature of 60°F that we experience.

Greenhouse Gases Water Vapor: 0-4% Carbon Dioxide (CO2): 0.036% Methane (CH4): 0.00017% Nitrous Oxide (N2O): 0.00003% CFCs, HFCs, SF6

Global Greenhouse Gases

Evidence

Carbon Dioxide Levels in Relation to Global Temperature

Key Indicators Sea level Land Ice Carbon Dioxide Concentration Timing of the seasons Global Surface Temperature Allergy season Snowfall/Snowpack Arctic Sea Ice

Ragweed Pollen Season These trends are strongly related to changes in the length of the frost-free season and the timing of the first fall frost.

Cherry Tree blossom Peak 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.

First Freeze Freeze dates have shifted later by a rate of half a day to one day per decade.

Bird Migration Trends of northern movement are closely related to increasing winter temperature

Radiative Forcing Greenhouse gases produced by humans have caused overall warming influence on Earth’s climate since 1750. Carbon dioxide is by far the biggest contributor.

Evidence Sea Level Rise Global Temperature Rise Global sea level rose 17 cm (6.7 in) in the last century Rate in the last decade nearly double that of the last century Global Temperature Rise Earth has warmed since 1880 with most of warming occurring since the 1970s 20 warmest years occurred since 1981 10 warmest years occurred in the past 12 years

Evidence Warming Oceans Shrinking Ice Sheets Top 700 m (2,300 ft) of ocean showing warming of 0.302°F since 1969 Shrinking Ice Sheets Greenland: lost 150-250 km3 (36-60 cubic miles) of ice per year between 2002 and 2006 Antarctica: lost 152 km3 (36 cubic miles) of ice between 2002 and 2005

Evidence Declining Arctic sea ice Glacial retreat Extent and thickness of Arctic sea ice has declined rapidly over last several decades Glacial retreat Retreating almost everywhere around the world including Alps, Himalayas, Andes, Rockies, Alaska, and Africa

Evidence Extreme Events Ocean Acidification Number of record high temps increasing since 1950 Number of record low temps decreasing since 1950 Increasing numbers of intense rainfall events Ocean Acidification CO2 content of oceans increasing since 1750 Currently increasing 2 billion tons per year Increased ocean acidity by about 30%

IPCC Intergovernmental Panel on Climate Change Group of scientists from around the world that review and assess information on climate change Climate models and projections

Projections for North America Decreasing snowpack in the western mountains 5-20% increase in yields of rain-fed agriculture in some regions Increased frequency, intensity and duration of heat waves

Projections for Latin America Gradual replacement of tropical forest by savannah in eastern Amazon Risk of significant biodiversity loss through species extinction in many tropical areas Significant changes in water availability for human consumption, agriculture, and energy generation

Projections for Europe Increased risk of inland flash floods More frequent coastal flooding and erosion Glacial retreat in mountainous areas Reduced snow cover and winter tourism Extensive species losses Reductions of crop productivity in South Europe

Projections for Africa By 2020, 75-250 million people are projected to be exposed to increased water stress Yields from rain-fed agriculture could be reduced by up to 50% in some regions by 2020 Agricultural production, including access to food, may be severely compromised

Projections for Asia Freshwater availability projected to decrease by 2050 Coastal areas at risk for increased flooding Death rate from disease associated with floods and droughts expected to rise

Wisconsin’s Climate 1950-2006 Average temperature increased 1.5°F Greatest amount of warming in winter and spring, especially NW Wisconsin Nighttime lows warming faster than daytime highs, especially in summer Decline in extremely cold winter nights, especially in NW Wisconsin Date of last spring freeze occurring 6-20 days earlier Date of first fall freeze occurring 3-8 days later Growing season increased up to 4 weeks Annual average precipitation increased 15% although parts of the North became drier

Wisconsin’s Future Climate Projections 4-9°F increase by mid-21st Century Warming most pronounced in winter Fewer extremely cold winter nights and more hot summer days Probability of greater than 3 in. rainstorms will increase during spring and fall

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

Projected change in average winter temperature from 1980 to 2055 Projected change in annual temperature from 1980 to 2055

Madison Lakes Ice cover http://climatewisconsin.org/story/ice-cover

Temperature Change http://climatewisconsin.org/story/temperature-change

Shipping on the Great Lakes http://climatewisconsin.org/story/great-lakes-shipping