APES Chapter 19

Greenhouse Effect

*one of planet's most important forms of natural capital radiation from earth's atmosphere warms the surface of the planet; without it, the planet would be uninhabitable

Uncertainty of Clouds role in atmospheric warming

*warmer temps increase evaporation of surface water= increases relative humidity & creates more clouds thick cumulonimbus clouds could make planet cooler by reflecting more sunlight back into space wispy cirrus clouds could cause warming of atmosphere by preventing heat from escaping

Explain TWO climate change tipping points

- atmospheric CO2 levels, need to prevent them from reaching 450ppm- estimated tipping point - global average atmospheric temperate, can no longer avoid a global temp rise of more than 2 degrees Celsius (3.6 degrees F)

Water Vapors role in the atmosphere

66% of earth's greenhouse effect but stays in atmosphere for only 1-3 weeks (other gases stay years) *as air warms, it is able to hold more water vapor-- the warming effect of other greenhouse gases leads to an increased amount of water vapor, which augments greenhouse effect (scientists consider CO2 to be main generator for atmospheric warming related to gases)

Ocean Acidification

CO2 absorbed by ocean reacts with water to produce carbonic acid (H2CO3)-- result of CO2 emissions by humans

Greenhouse Gases

H2O (water vapor), CH4 (methane), CO2 (carbon dioxide), N2O (nitrous oxide) also includes HFCs, CFCs, HCFCs, Ozone

Montreal Protocol

agreed on September 16, 1987; went into affect January 1, 1989- international treaty designed to protect ozone layer and eliminate substances that are responsible for its depletion; as a result, ozone hole in Antarctica is slowly recovering:)

Human activities that add CO2 to the atmosphere.

burning of fossil fuels, deforestation

Effects of rise of sea levels

degradation of estuaries, wetlands, coral reefs; disruption of fisheries; flooding & submersion of low-lying islands and sloping coastlines; saltwater contamination of freshwater coastal aquifers

Greenland's Glaciers

due to atmospheric warming, Greenland's glaciers have begun to melt at an accelerating rate. these glaciers contain up to 10% of world's freshwater, which melted would be enough to raise the global sea level as much as 7 meters (23 feet). they're getting thinner at their ocean outlets, which causes it to float away from the ground at shore and accelerates its flow toward the sea. melting glaciers in the sea push down the heavier saltwater which changes the ocean currents *don't forget that once a glacier melts, it leaves a dark spot, which now absorbs heat; the white of the glacier used to reflect back the sun's heat

Suns role in atmospheric warming

energy output from sun has always varied, and some people think global warming is due to increased output from sun. this is false, evidence has shown that the stratosphere is cooling white the troposphere is heating up, which is the opposite of what would happen if the sun were increasing its solar output (evidence shows solar output has even decreased a bit)

Factors that make dealing with Climate Change hard

global problem, reacquires prolonged international cooperation; long-term political issue (voters & elected officials usually respond better to short-term probs); projected harmful & beneficial impacts of climate disruption are not spread evenly; many proposed solutions are controversial (could disrupt economies/ life styles); difficult to convince public how important this issue is

Major Prevention Strategies (4)

improve energy efficiency to reduce fossil fuel use shift from carbon-based fossil fuels to low-carbon renewable energy resources stop cutting down tropical rain forests/ plant trees to help reduce CO2 levels shift to more sustainable and climate-friendly agriculture

Human activities that add nitrous oxides to the atmosphere

increased use of nitrogen fertilizers (remains in atmosphere for 114 years & each molecule has nearly 300 times the warming potential of a molecule of CO2)

Ways to clean up climate disrupption

remove CO2 from smokestack & vehicle emissions, plant trees & preserve forests and wetlands, isolate carbon in soil using bio char, storing CO2 deep underground or in ocean

Human activities that add methane to the atmosphere

livestock production, rice production, natural gas production, leaky coal mines, landfills, flooding of land behind large dams

How scientists determine climate

look at data of fluctuating weather conditions for a particular area over a period of at least 30 years-- short term changes in weather do not define climate

Geoengineering

manipulate certain natural conditions to help counter enhanced greenhouse effect

Approaches to deal with climate change effects

mitigation- act slow & avoid tipping points adaptation-- recognize some climate change is unavoidable and try to reduce some of its harmful effects

Oceans role in atmospheric warming

oceans absorb CO2 from the atmosphere through carbon cycle-- helps regulate earth's climate; they remove 1/3 of CO2 pumped into lower atmosphere by human activities & absorb heat from lower atmosphere. *ability of oceans to absorb CO2 decreases as water temps rise; as they warm, some of dissolved CO2 is released back into lower atmosphere. heating of oceans also causes them to become more acidic

Atmospheric Warming/Cooling 900,000 years ago vs during this century

over 900,000 years, earth has experienced gradual global cooling (glacial period- freezing) & global warming (interglacial period-thawing) for past 1,000 years, E's temp remained fairly stable in interglacial period, but during 19th& 20th century temp began to rise **most of recent increase in global average temp has taken place since 1975 and has increased since

Climate Change Tipping Point

point at which an environmental problem reaches a level that could cause irreversible damage (no going back)

Ways to prepare for climate disruption

projects such as expanding mangrove forests, build shelters on high ground, plant trees on slops to prevent landslides; flood-control barrier, improve forest fire-fighting capabilities & proposing desalination plants to help relieve projected water shortages

Causes of global change

prolonged drought/ heat waves, floods, wildfires, collapsed ecosystems, extinction of up to half of world's species, spread of tropical infectious diseases

How scientists get info on past temps/climates

radioisotopes in rocks/fossils, ocean sediments; bubbles, layers of soot & other materials trapped in different layers found in ice cores from glaciers; tree rings

Carbon Capture and Storage (CCS)

removing CO2 from exhaust coming out of smokestacks at power plants by pumping it deep underground in abandoned coal beds or liquefy it & inject it into sediments under seafloor (would take many years, could promote more use of coal, takes a lot of energy, reduced net energy yield & raise cot of burning coal to provide electricity, not guaranteed that there wouldn't be any leaks)

Advantages of carbon/energy taxes

simple to administer, clear price on carbon, covers all emitters, predictable revenues

Disadvantages of carbon/energy taxes

tax laws can get complex, vulnerable to loop holes, doesn't guarantee lower emissions, politically unpopular

Greenhouse Gas Emissions US vs China

together account for 41% of world's annual greenhouse gas emissions china leading emitter of CO2 since '07 but per capita emissions are low b/c most members of its population are too poor to use large amount of fossil fuels US emits almost 3 times as much CO2 per person as China

What you can do to reduce carbon emissions

use low-flow shower head, eat less/ no meat, plant trees, support businesses working to reduce their emissions, wash clothes in warm/ cold water and hang them to dry

Why the current atmospheric warming probably urgent

we face a rapid projected increase in the average temperature of the lower atmosphere during this century-- will rapidly change the mild climate that we have had for the past 10,000 years

Weather vs Climate

weather- short-term changes in the atmosphere (temperature, rain, wind, etc) climate- average weather conditions of an area over a long period of time

Effects on warmer atmosphere on ice, permafrost and sea levels

will cause ice to melt & thin/ its volume to decline, sea levels will rise, permafrost will melt and release greenhouse gases (carbon dioxide, methane)