APES ch. 18
mitigation
pursue actions that reduce greenhouse gas emissions in order to lessen severity of future climate change - aim is to alleviate problem ex: - improve energy efficiency - clean and renewable energy sources - farm practices that protect soil quality - recovering landfill gas - preventing deforestation
Ozone concentrations in TROPOSPHERE have risen by what percent since 1750? What has caused this.?
- risen by 36% - mostly due to photochemical smog
The Great Wall of Male
- seawall intended to protect buildings and roads
Where are temperature changes greatest? What Is going on in this region?
- Arctic - here, ice sheets are melting, sea ice is thinning, storms Increasing, and humans and wildlife affected - As sea ice melts earlier, freezes later, and recedes from shore, hard for Inuit and Polar bears to live (Polar bears can't hunt seals) - permafrost (permanently frozen ground) is thawing in Arctic, destabilizing buildings. Strong wind is contributing to sea-level rise by melting ice caps an ice sheets
If we were to cease greenhouse gas emissions today, temp would still rise by how much per decade and why?
- 0.1 Celsius (0.2 F) - this is because time lag from ases already present in atmosphere that have yet to exert they full influence
The IPCC report concludes that average surface temperature on Earth increased by ___ between 1906 and 2005
- 0.74 degrees Celsius (1.33 Fahr.)...most increase in last few decades
Earth today compared preindustrial Earth of 1750 is experiencing overall radiative forcing of ___
- 1.6 watts/m^2 - Earth is estimated to receive and give off 342watts/m^2 of energy. 1.6 watt still/m^2 is big enough fraction of 342 alter climate significantly
Milankovitch cycles
- 1920s serbian mathematician Milutin Milankovitch described three types of periodic changes in Earth's rotation an orbit around the sun - these variations alter way solar radiation is distributed over Earth's surface n - by modifying patterns of atmospheric heating, these cycles trigger long-term climate variation like periodic episodes of glaciation
What percent of the American population lives in coastal areas?
- 53% -
Describe the role of greenhouse gases
- As Earth's surface absorbs solar radiation, the surface increases in temperature and emits infrared radiation, radiation with longer wavelengths than infrared light - greenhouses gases absorb this infrared light very effectively - these gases include water vapor, ozone (O3), Carbon dioxide, nitrous oxide (N2O), and methane (CH4), as well as hydrocarbons (include chlorofluorocarbons) - after absorbing radiation emitted from surface, greenhouse gases subsequently re-emit infrared energy of slightly different wavelengths - some of this energy travels downward, warming the atmosphere and planet's surface (greenhouse effect)
How could a positive feedback mechanism w water vapor increase greenhouse gas effect?
- As tropospheric temperatures continue to increase, Earth water bodies should transfer more water vapor into atmosphere
What the fricking sh*t is going on in the Maldives?
- a nation of islands in the ocean ocean known for spectacular coral reefs. - fear that it could be submerged by rising seas created by climate change - 80% of land area lies less than 1m above sea level. - salt water flooding could contaminate drinking water - storms intensified by warmer waters wil erode beaches, cause flooding, and damage coral reefs vital for fishing and tourism - government recently evacuated residents from some islands - tsnuami struck in 2004 ($470 million of damage in Maldives, 62% of GDP)...not caused by climate change but shows effect of rising sea level
Radioactive forcing
- amount of change in energy that a given factor causes - quantitative measurement of the degree of influence that aerosols,greenhouse gases, and other factors exert over Earth's energy balance - positive forcing warms surface and negative forcing cools it
What is one reason warming is accelerating in the Arctic?
- as snow. Ice melt, darker, less reflective surfaces are exposed and Earth's albedo (capacity to reflect light) decreases - as a result, more of suns rays absorbed at surface , fewer reflected and surface warms - positive feedback loop
What are the effects of higher sea levels
- beach erosion - coastal flooding - intrusion of saltwater into aquifers
Stern Review
- british gov't - said climate change could cost 5-20% of GDP by 2200 but that investing just 1% of DP starting now would enable us to avoid future costs
Nitrous oxide as a geeenhouse gas
- by-product of feedlots, chemical manufacturing plants, auto emissions, and synthetic nitrogen fertilizers has risen by 18% since 1950
U.S. climate action partnership
- companies joined together to ask government leaders to enact strong national legislation to require significant reduction of greenhouse gas emissions (GM, shell, pg and e) - these companies joined with insurance companies
Is water vapor viewed as having driven industrial-age climate change?
- concentrations vary locally, but global concentration has not yet changed over recent centuries, so it is NOT viewed as having driven industrial-age climate change
Two threats posed by climate change on coral reefs
- coral bleaching by warmer waters - enhanced CO2 concentrations in atmosphere are changing ocean chemistry As ocean water absorbs CO2 it becomes more acidic which impairs growth of coral
U.S.Global Change Research Program
- created by congress in 1990 to coordinate federal climate research - report highlighting past and future effects of global climate change on U.S., where avg temp increased by 0.6 degrees celsius during 20th century - used computer models - presented graphs summarizing predicted impacts of climate change - concluded forest communities would shift northward and upward in elevation - forests like oak-hickory and oak-pine would increase in U.S. while others decline - predicted that of 16 crops in U.S., yields of 13 would increase and that of potato would decrease - said to be suppressed by Bush administration
More problems of rising sea levels
- damage to coral reefs (often critical to Maldive economy). Coral reefs provide habitat for food, tourism attraction, and reduce wave intensity. - rising sea levels will eat away at coral reefs, mangrove forests, salt marshes
Charles Keeling
- documented trends in atmospheric carbon dioxide concentration starting in 1958 - collected four air samples from five towers every hour - data shows that atmospheric CO2 concentration have increased from 315 ppm in 1958 to 383 ppm in 2007
How will climate change effect agriculture?
- earlier springs require earlier crop planting - For some crops in temperate zones, production may increase slightyly with moderate warming - droughts and floods can become more severe - overall global crop yields expected to increase somewhat, but beyond rise of 3 degrees celsius, crop yields expected to decline - growing seasons shortened in seasonally dry tropical and subtropical regions and harvests more susceptible to drought
global warming potential
- greenhouse gases differ in ability to warm troposphere and surface - global warming potential refers to relative ability of one molecule of a given greenhouse gas to contribute to warming - values are depressed in relation to CO2, which is assigned a global warming potential of 1 1) Hydrochlorofluorocarbon (HFC-23) = 12,000 ( heat trapping ability in CO2 equivalents) 2) Nitrous Oxide (N2O) = 296 3) Methane (CH4) = 23 4) Carbon dioxide (CO2) = 1
greenhouse skeptics
- handful of scientists typically backed from exxon-mobil and other fossil fuel and auto companies - aimed to cast doubt on scientific consensus
The oceans have de erased by how many pH units? By how much pH are oceans expected to decline in next century?
- have declined by 0.1 pH units - predicted to decline in pH by 0.14-0.35 more units over next 100 years
What negative feedback loop do plants create with global warming? How could it become a positive feedback loop?
- if climate change increases vegetative growth, it could help mitigate carbon emissions as plants intake carbon - if climate change decreases vegetative growth (like drought or fire), then positive feedback could increase carbon flux to atmosphere
How does climate change effect animals and environment ? N eco
- in spring, birds are migrating earlier, insects hatching earlier, and animals breeding earlier - plantings are leafing up earlier ( called "greening up") - great tits (legit name of a bird LOLXDXDLOL) are affected by plants leafing earlier - plants and animals moving toward poles or upward in elevation - as many as 20-30of plant and animal species could be threatened with extinction - trees may not be able to shift distributions fast enough - mountain animals may be forced uphill - erosion and flooding will pollute and alter aquatic systems - acidification of oceans will pose threats for coral reefs and other marine animals Many impacts on ecological systems will reduce ecosystem Goods and service we receive from nature , from food, to clean air to drinking water
Intergovernmental panel on Climate Change (IPCC)
- international panel of scientists and government officials established in 1988 by United Nations Environment Program (UNEP) and World Meteorological Organization - 2007, IPCC released its Fourth Assessment Report, which represents consensus of scientific climate research from around world Fourth assessment report - summarizes thousands of scientific studies and documents observed trends in surface temperature, precipitation patterns, snow and ice covers sea levels, storm intensity, and other factors - also predicts future changes in phenomena - addresses impacts of current and future climate change on wildlife, ecosystem and human societies - discusses possible strategies we might pursue in response to climate change - summarizes a selection of IPCC report's major observed and predicted trends and Impacts - estimates regarding impacts of change on human societies are conservative, because conclusions had to be approved by reps of world governments (some reluctant to move from fossil fuels)
How will climate change affect forestry?
- invasive species - outbreak of insects and diseases - catastrophic fires -for timber and forest products, enriched CO2 may spur greater growth in short term - droughts will effect forestry - El Nino in 1997-8 allowed immense forest fires to destroy millions of ha of rainforest in brazil, mexico, eslewhere
International polar yesr
- large international scientific program coordinating research in the Arctic and Antarctic
Fourth Assesment Report of the Intergovernmental Panel on Climate Chnage (2007)
- made clear to world that the scientific consensus is that climate is changing, that we are the cause, and that climate change is already exerting impacts that will become increasingly more severe if we do not take action
Aerosols
- microscopic droplets and particles which can have either a warming or cooling effect on the atmosphere - ,out tropospheric aerosols cool atmosphere by reflecting the sun's rays -
How will climate change affect health?
- more heat waves and heat stress can cause death - heat wave in 1995 in Chicago killed hundreds - heat wave in 2003 in europe killed 35,000 other health problems: - respiratory ailments from air pollution, cuz hotter temp. creates photochemical smog - expansion of tropical disease like dengue fever into temperate regions - floods overcome sewage treatment systems - injuries and drowning if storms become more frequent and intense - hunger as demands on agriculture increase
How could a negative feedback that reduces global warming occur w water vapor?
- more water vapor could give rise to increased cloudiness which might slow global warming by reflecting more solar radiation back into space - depending on wether low or high elevation clouds result, they might either shade and cool earth or contribute to warming and accelerate evaporation and further cloud formation (positive feedback loop)
What has caused CO2 levels in atmosphere to increase so quickly?
- most carbon is stored for a long time in upper layers of lithosphere - the deposition, partial decay and compression of organic matter (mostly plants) that grow in wetland or marine areas during Carboniferous period (290-350mya) led to formation of fossil fuels in sediment. In absence of Human activity, these reservoirs would be practically permanent - over past 200 years we've burned fossil fuels in homes, industry, cars, transferring large amounts of carbon f on underground deposits to atmosphere. Flux of carbon from lithosphere to atmosphere is main reason atmospheric CO2 concentrations have increased so much. - people also clear and burn forests to make room for crops, pastures and cities. Forest serve as sinks for active carbon and their removal reduces biospheres ability to absorb CO2 from atmosphere. Deforestation has contributed to rising CO2 levels.
Carbon dioxide and its effect on climate change
- not most potent greenhouse gas, but far more abundant in atmosphere than gases like methane and nitrous oxide , so contributes more to greenhouse effect - human activities have boosted earths atmospheric concentration of CO2 from 280 ppm as recently as late 1700s to 383ppm in 2007 - The CO2 concentration is at its highest level in over 650,000 years and likely highest in last 20 million
ocean absorption
- ocean holds 50x more carbon than the atmosphere, and they absorb carbon through atmosphere by direct solubility of gas in water and through uptake by marine phytoplankton for photosynthesis - oceans absorb CO2 more slowly than we are adding CO2 to the atmosphere - carbon absorption by oceans is slowing global warming but not preventing it - evidence indicates that absorption is decreasing. As ocean water warms it absorbs less CO2 because gases less soluble in warm water (positive feedback loop that accelerates warming)
ocean circulation
- ocean water exchanges heat w atmosphere. Ocean currents move energy - in equatorial places, oceans receive more heat from sun then they emit. Near poles, oceans emit more heat than they receive. - cooling water at pole tends to sink and the warmer surface water from equator takes its place
Qué pasa en Glacier National Park in Montana?
- only 27 of 150 glaciers present at the parks inception remain
Se La Niña
- opposite of El Niño - cold surface water extend far westward into equatorial Pacific and weather patterns affected in oposite way -
coupled general circulation models (climate models)
- programs that combine what is. Known about atmospheric circulation, Ocean circulation, atmospheric ocean interactions, and feedback mechanisms to simulate climate processes - couple climate influences of atmosphere and oceans in simulations
How is efficacy of climate models tested?
- researchers enter past data. If a model produces accurate reconstructions of past and current climate, then it is believed to be accurate predictor of future climate
What are projections for how global warming is and will effect Poles?
- snow cover, permafrost, and ice sheets are projected to decrease - sea ice will continue to shrink in both poles - some scenarios show Arctic ice decreasing completely by late 21st century, creating new shipping lane and rush to exploit underwater deposits of oil and minerals
Effects of rapid melting of mountain glaciers
- sudden floods as ice dams burst - reduce summertime water supply to millions
Sulfate aerosols
- sulfate aerosols produced by fossil fuel combust on may slow global warming, at least in the short term. -When SO2 enters the atmosphere it undergoes various reactions, some of which lead to acid precipitation. These reactions, along w volcanic tiñoso csn contribute to the formation of a sulfur rich aerosol haze in upper atmosphere that reduces the amount of sunlight that reaches Earth's surface - aerosols released by major volcanic eruptions can exert short term cooling effects on Earth's climate for several years
What three factors exert the most influence on Earth's climate than all others combined?
- sun (without it, earth would be dark and frozen) - atmosphere (earth would be as much as 33 degrees Celsius colder and temp differences between night and day would be far greater) - oceans (shape climate by storing and transporting heat and moisture)
Solar Output
- sun varies over radiation it emits over short and long time scales - at each peak of 11 year sun spot cycle, the sun emits solar flares, bursts of energy strong enough to disrupt satellite communications - variation In solar energy reaching planet not great enough to drive significant temp change - radiative forcing of natural changes in solar output at only 0.12watss/m^2
El Niño - Southern Oscillation (ENSO)
- systematic shift in atmospheric pressure, sea surface temp. And ocean circulation in tropical Pacific Ocean - normally, prevailing winds blow from east to west long equator (regio of pressure to low pressure) forming large scale convective loop. Wind push surface water westward, causing water to pile up in western Pacific. Water can be warmer and higher in western Pacific as a result. - El Niño conditions are triggered when air pressure increases in the Western Pacific and decreases in eastern Pacific, causing equatorial winds to weaken. Without winds, warm water that collected in western Pacific flows eastward, suppressing upwellings along coasts of America and shutting down delivery that supports marine life and fisheries
Storm surge
- temporary and localized rise in sea level brought on by the high tides and wind associated with storms
Proxy indicators
- types of indirect evidence that serve as proxies or substitutes for direct measurement and that she'd light on past climate Example: - earth ice caps,ice sheets and glaciers preserve within them tiny bubbles of ancient atmosphere. By examining bubbles, scientist an determine atmospheric composition, greenhouse gas concentrations, temperature trends, snowfall, solar activity and (from trapped soot particles) frequency of forest fires - scientists have extracted ice cores in Antarctica and have been able to go back in time 740,000 years read ping earth's history across glacial cycles - reasearchers also drill cores into beds of sediment beneath bodies of water. Sediments also preserve pollen grains and remnants from plants. Knowing what plants occurred in a location at a given time can tell us much about the climate - the width of each ring of a tree trunk reveals how much the tree grew in a particular growing season; a wide ring means more growth, generally indicating a wetter year. Also used to study fire hidtory since a charred ring indicates a fire. Bristlecone pins are long lived and can provide record of prec. And drought going hundreds or thousands of years. Pack rat midden are valuable source of climate change as well, - living coral reefs take in trace elements and isotope ratios from ocean water and incorporate chemical clues to ocean conditions into growth bands in the structure of reefs they build - proxy indicators often need to be combined to provide global perspective as they are often local indicators
Methane as a greenhouse gas
- we release met Haney tapping into fossil fuel deposits, raisin livestock that emit methane as a metabolic waste, disposing of organic matter in landfills, and growing certain crops such as rice - since 1750, atmospheric methane concentrations have risen 2.5-fold - today's concentration highest by far in 650,000 years
How will climate change effect economics?
- widen gap between rich and poor - poorer nations have less wealth and tech. with which to adapt to climate change, and poorer people rely more on resources that are sensitive to climatic conditions - climate change will cost 1-5% of GDP on average globally. poor nations will lose more proportionally - social cost of carbon is $10-$350 per ton of carbon
thermohaline circulation
- worldwide current system in which warmer, fresher water moves along surface and colder, saltier water moves deep beneath surface - in Atlantic Ocean, warm surface water flows s northward from equator in the Gulf Streak, carrying heat to high latitudes - as surface water of this conveyor belt system releases heat energy and cools, it becomes denser and sinks, creating the North Atlantic Deep Water
Measurements for sea level rises in 20th century
- worldwide, sea levels rose 17cm during 20th century - seas rose by 1.8 mm/year from 1961-2003 and 3.1mm/year from 1993-2006
How would interrupting thermohaline circulation trigger rapid climate change?--2
-lif global warming causes much of Greenland ice sheet to melt, fresh water runoff from North Atalantic would dilute surface waters, making them less dense (fresh less dense than salt water) - this could stop the North Atlantic Deep Water formation and shut down northward flow of warm equatorial water causing Europe to cool rapidly. - thermohaline circulation is already slowing -not sure whether Greenland runoff will cause shutdown this century (many say It won't)
impacts of El Nino
-upwelling does not occur -brings severe weather for land - coastal industries like Peru anchovy fisheries devastated - alter weather events around world, creating rainstorms and floods in dry area like SoCal and droughts and fire in moist areas like Indonesia
In future, we can expect average surface temp on Earth to rise ____ per decade for next 20 years
0.2 degrees Celsius (0.4 F)
At the end of the 21st century, the IPCC predicts global temp. will be ____ higher than today's, depending upon emission scenario
1.8-4.0 Celsius (3.2-7.2 F)
Over what fraction of the worlds people live in regions supplied by mountain meltwater?
1/6
by how much did the world's ocean rise in the 20th century ?
10-20cm (4-8 in)
Methane as a greenhouse gas
508
Nitrous oxides as a greenhouse gas
508
climate
Area's long term atmospheric conditions, including temp., moisture content, wind, precipitation, barometric pressure, solar radiation, and other characteristics
Emissions of greenhouse gasses in U.S. are mostly from ____
CO2 (Not most global warming potential, but most abundant in our emissions)
What is he fastest moving area of environmental science today?
Climate change
Global c,image change
Derribes trends and variations in Earths climate, invoking aspects such as temp., precipitation, and storm frequency and intensity
How is global warming different from climate change?
Global warming refers specifically to an increase in Earth's average surface temp whereas climate change is change in various aspects of earth climate like precipitation, temp, and storm frequency and intensity
What is the most abundant greenhouse gas in atmosphere?
Water vapor (Contributes most to greenhouse effect)
adaptation
accept that climate change is happening and to pursue strategies to minimize impact on us - adapt to change examples: - maldive's great wall of male - restrict coastal development - farming coping with drought - modifying water management practices to deal with reduced river flows, glacial outburst floods, or salt contamination of ground water
