Climate Change Global Climate Change We warn you
Climate Change
Global Climate Change “We warn you that unless you act quickly and decisively, our homeland others like it will disappear beneath the rising sea before the end of this century. ” - Mohamed Nasheed, former president of the Maldives 2
Weather and Climate Are Not the Same • Weather is short-term changes • Temperature • Air pressure • Precipitation • Wind • Climate is average conditions in a particular area over a long period of time • Temperature • Precipitation • Fluctuations are normal
Climate Change is Not New • Over the past 4. 7 billion years the climate has been altered by • Volcanic emissions • Changes in solar input • Movement of the continents • Impacts by meteors • Changing global air and ocean circulation • Over the past 900, 000 years • Glacial and interglacial periods
�Some of the infrared energy from the sun penetrates the atmosphere, warming the Earth’s surface. �The infrared energy is then re-radiated off the Earth’s surface, back towards space. � Some of that energy is kept at the surface by the troposphere. 5
Greenhouse Effect �The trapping of some of the infrared radiation within the atmosphere keeps the Earth’s daily temperature fluctuations within a small, habitable range. �This is called the greenhouse effect. �The greenhouse gases responsible for this effect include: �Chloroflurocarbons (CFCs) �Nitrous oxide �Methane �Carbon dioxide �Water vapor 6
�Mars, a sister planet to the Earth, has a much thinner atmosphere and no significant greenhouse effect. �A Martian summer daytime high near the equator may approach 70°F. �At night, the same location would experience a low of -100°F. 7
GHG NOT • Sulfur dioxide (S 02) is not a GHG • SO 2 has a cooling effect on earth • Major sources – volcanic eruptions and burning coal.
Proxies � Temperature data prior to the 19 th century is the result of proxies, or indirect measurements. � Ice cores are drilled into the glaciers in Antarctica and Greenland. � Dissolved bubbles of atmosphere in each layer are analyzed � Two gases are analyzed in each ice core layer. � Relative amounts of two isotopes of oxygen can be used to estimate the temperature at the time the ice was formed. � Concentration of greenhouse gases, like carbon dioxide and methane, are measured directly. � These measurements have been used to create graphs showing atmospheric changes during the lifespan of the glaciers. 9
Tracking Global Climate Change �In 1958, measurements of atmospheric carbon dioxide levels were directly sampled at an observatory in Mauna Loa, Hawaii. � Hawaii was chosen to avoid the influences of large forests or cities. 10
�Carbon dioxide levels fluctuate within each year, depending on the season of the Northern Hemisphere. � Slightly higher CO 2 in the winter. � Slightly lower CO 2 in the summer. �Overall trend shows a steady increase. 11
�Both land ocean surface temperatures have increased since the industrial revolution. � 0. 76°C increase in air temperature since 1850. � Current rate of 0. 13°C per decade. Source: Climate Change Key Indicators climate. nasa. gov/key_indicators 12
�Sea ice is frozen seawater that floats on the ocean’s surface. �The Arctic reaches its minimum sea ice extent each September, at the end of summer. � September Arctic sea ice extent is declining at a rate of 11. 5% per decade. Source: Climate Change Key Indicators climate. nasa. gov/key_indicators 13
�Land ice includes glaciers, ice sheets, ice caps, and permafrost. � Currently losing 24 cubic miles of ice per year in Antarctica. Source: Climate Change Key Indicators climate. nasa. gov/key_indicators 14
�One of the reasons why the Arctic is heating so much faster is the difference in albedo between snow and ocean water. �Albedo is a measurement of how reflective a surface is. �Ocean water has a much lower albedo, so more heat is absorbed as the ice melts. 15
Human Activities Emit Large Quantities of Greenhouses Gases • Since the Industrial Revolution • CO 2, CH 4, and N 2 O emissions higher • Main sources: agriculture, deforestation, and burning of fossil fuels • Correlation of rising CO 2 and CH 4 with rising global temperatures
Human Activities & Climate Change • Intergovernmental Panel on Climate Change (IPCC), with 2010 updates • 90– 99% likely that lower atmosphere is warming • Especially since 1960 • Mostly from human-caused increases in greenhouse gases • Increased greenhouse gas concentrations will likely trigger significant climate disruption this century • Ecological, economic, and social disruptions
Agriculture • • Water Resources Shifts in food-growing areas • Changes in water supply Changes in crop yields • Decreased water quality Increased irrigation demands Increased pests, crop diseases, and weeds in warmer areas • Increased drought • Increased flooding Forests • Changes in forest composition and locations • Disappearance of some forests • Increased fires from drying • Loss of wildlife habitat and species Biodiversity Sea Level and Coastal Areas • Extinction of some plant and animal species • • • Loss of habitats • • Disruption of aquatic life • • • Weather Extremes • Prolonged heat waves and droughts • Increased flooding • More intense hurricanes, typhoons, tornadoes, and violent storms Rising sea levels Flooding of low-lying islands and coastal cities Flooding of coastal estuaries, wetlands, and coral reefs Beach erosion Disruption of coastal fisheries Contamination of coastal aquifiers with salt water Human Health Human Population • Increased deaths • More environmental refugees • Increased migration • Increased deaths from heat and disease • • Disruption of food and water supplies • • Increased respiratory disease Spread of tropical diseases to temperate areas Increased water pollution from coastal flooding
Severe Drought Is Likely to Increase • Accelerate global warming, lead to more drought • Increased wildfires • Declining stream flows, dry lakes, lower water tables • Dry climate ecosystems will increase • Other effects of prolonged lack of water
More Ice and Snow Are Likely to Melt • Glaciers disappearing from • Himalayas in Asia – major source of fresh water in Asian nations • Alps in Europe • Andes in South America • Decrease in albedo: increased rate of melting of ice caps
�Polar bears are highly dependent on sea ice to hunt seals, their primary food source. �With sea ice in decline, the polar bear population is expected to decline by two-thirds by 2050. �Whether they go extinct depends on their ability to adapt to finding terrestrial food sources. A “pizzly” or “grolar bear” hybrid caught by a hunter in Canada’s Northwest Territories in 2007. 21
Temperate Glaciers �Only about 1% of the world’s land ice is located in temperate, or non-polar regions. �Mostly within mountain ranges. A 1870 postcard of the Rhone glacier in Switzerland contrasted with a 2006 view. Source: New York Times 22
Melting of Alaska’s Muir Glacier between 1948 and 2004
Sea Level Rise �As the ocean level rises, it will impact coastal cities. �Half of the surrounding area of Miami, for example, is only 5 feet above sea level. Sand on highway A 1 A swept over a sea wall in Ft. Lauderdale, Florida by Hurricane Sandy in 2012. 24
Pensacola Tallahasee Jacksonville Atlantic Ocean Orlando Gulf of Mexico Tampa FLORIDA Fort Meyers Naples Miami Key West Fig. 19 -8, p. 509
Permafrost Is Likely to Melt • If permafrost in Arctic region melts • Methane, a greenhouse gas, will be released into the atmosphere • Arctic permafrost contains 5060 x the amount of carbon dioxide emitted annually from burning fossil fuels • Methane in permafrost on Arctic Sea floor
Sea Levels Are Rising • Thermal expansion of warmer sea water – SL rise • Melting of land-based ice • Effects: • Flooding of coast cities • Disruption of coastal fisheries • Flooding of • Low-lying barrier islands and coastal areas • Agricultural lowlands and deltas • Contamination of freshwater aquifers
Climate Disruption Is a Threat to Biodiversity • Migratory animals • Forests • Which organisms could increase with global warming? Significance? • Insects • Fungi • Microbes
�Warmer temperatures have increased the range of many pest insects. � Mosquitoes that spread diseases like malaria and West Nile Virus have expanded ranges. � Pine bark beetles have begun infesting boreal forests east of the Rocky Mountains. �Historically, these forests would have been too cold and out of their range. Dixie National Forest, Utah, United States. 29
Hurricanes �No significant link has been found between global warming and hurricane frequency. �It is likely that hurricanes will increase in intensity by 2 -11% by the end of the 21 st century. Promotional poster for An Inconvenient Truth, 2006. 30
Agriculture Could Face an Overall Decline • Regions of farming may shift • Decrease in tropical and subtropical areas • Increase in northern latitudes • Less productivity; soil not as fertile • Hundreds of millions of people could face starvation and malnutrition
Projected Effects of Global Warming and Resulting Changes in Global Climate Stepped Art Fig. 19 -7, p. 507
Solutions Slowing Climate Disruption Prevention Cut fossil fuel use (especially coal) Shift from coal to natural gas Improve energy efficiency Shift to renewable energy resources Transfer energy efficiency and renewable energy technologies to developing countries Reduce deforestation Cleanup Remove CO 2 from smokestack and vehicle emissions Store (sequester) CO 2 by planting trees Sequester CO 2 in soil by using no -till cultivation and taking cropland out of production Sequester CO 2 deep underground (with no leaks allowed) Use more sustainable agriculture and forestry Sequester CO 2 in the deep ocean (with no leaks allowed) Put a price on greenhouse gas emissions Repair leaky natural gas pipelines and facilities Reduce poverty Use animal feeds that reduce CH 4 emissions from cows (belching) Slow population growth Fig. 19 -16, p. 513
What Can You Do? Reducing CO 2 Emissions
Trade-Offs: Carbon and Energy Taxes
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