Chapter 19 Flashcards
Over the past 900,000 years what had experienced prolonged periods of global cooling and global warming?
The troposphere
How much did the Philippines explosion cool the average temperature by, and after how long would it return to normal?
It would cool the earth by .5 degrees Celsius and after 15 months
What is true about the temperatures over the past 1000 years?
Temperatures have remained fairly stable but began to rise during the last century.
What do scientists learn about the past from tiny air bubbles trapped in ice cores?
Troposphere composition, temperature trends, greenhouse gas concentrations, solar snowfall and forest fire activity.
In what year did an ice core show the co2 levels in the troposphere are the highest they have been in 650,000 years?
2005
What three major facts shape the earth’s climate?
1) the sun
a. greenhouse effect that warms the earths’s lower troposphere and surface because of the presence of GREENHOUSE GASES
2) oceans store co2 and heat, evaporate and receive water, move stored heat to other parts of the world
3) natural cooling process through water vapor in the troposphere (heat rises)
What are the major greenhouse gases in the lower atmosphere?
Water vapor, carbon dioxide, methane, and nitrous oxide
Facts about the major greenhouse gases in the lower atmosphere
- these gases have always been present in the earth’s troposphere in varying concentrations
- fluctuations in these gases plus changes in solar output are the major factors causing the changes in tropospheric temperature over the last 400,000 years
What are the causes mostly of the increases in the greenhouse gases in the troposphere between 1860 and 2004?
Fossil fuel burning, deforestation, and agriculture
What evidence shows that the earth’s troposphere warming is mostly because of humans?
- the past 20th century was the hottest century in the past 1000 years
- since 1900, the earth’s average tropospheric temperature has risen .6 degrees Celsius
- over the past 50 years, Arctic temperatures have risen almost twice as fast as those in the rest of the world
- glaciers and floating sea ice are melting and shrinking at increasing rates
Warmer temperatures in what states are melting permafrost and releasing more co2 and ch4 into the troposphere?
Alaska, Russia, and the arctic
During the last century, how much has the world’s sea level risen and what are the causes?
10-20 cm and mostly due to runoff from melting and land based ice and the expansion of ocean water as temperatures rise
What couple or combine the effects of the atmosphere and the oceans on climate?
Couples General Circulation Models (CGCMs)
FACTORS AFFECTING THE EARTH’S TEMPERATURE
- some factors can amplify (positive feedback) and some can dampen (negative feedback) projected global warming
- there is uncertainty about how much co2 and heat the oceans can remove from the troposphere and how long the heat and co2 might remain there
- warmer temperatures create more clouds that could warm or cool the troposphere
What can increased co2 in the troposphere cause?
- plant photosynthesis
- increase in plant photosynthesis would slow as the plants reach maturity
- carbon stored by the plants would be returned to the atmosphere as co2 when the plants die
- increased PS decreases the amount of carbon stored in the soil
- tree growth may temporarily slow co2 emissions in the Southern Hemisphere but is likely to increase co2 emissions in the northern hemisphere
Warmer air can release methane gas stored where?
Bogs, wetlands, tundra souls and will accelerate global warming
What nations would suffer the most in a warmer climate?
The tropics
Effect of global warming on ice?
Some of the worlds floating ice and land based glaciers are slowly melting and are helping warm the troposphere by reflecting less sunlight back into space
Between 1979 and 2005 how much has the arctic sea dropped by?
20%
Where are rising sea levels projected to flood?
Low-lying urban areas, coastal estuaries, wetlands, coral reefs and barrier islands and beaches
If sea levels rise by how much, what islands and their coral reefs will be flooded?
9-88 cm, Maldives islands
What effect could global warming have on ocean currents?
Alter ocean currents and cause both excessive warming and severe cooling
A warmer troposphere can?
Decrease the ability of the ocean to remove and store co2 by decreasing the nutrient supply for phytoplankton and increasing the acidity of water.
Global warming will lead to?
Prolonged heat waves and droughts in some areas and prolonged heavy rains and increased flooding in other areas
Global warming will increase deaths from:
- heat and disruption of food supply
- spread of tropical diseases to temperate regions
- increase the number of environmental refugees
Climate change is such a difficult problem to deal with because:
- the problem is global
- the effects will last a long time
- the problem is a long term political issue
- the harmful and beneficial impacts of climate change are not spread evenly
- many actions that might reduce the threat are controversial because they can impact economies and lifestyles
Reduces greenhouse gas emissions
Mitigation
We recognize that some warming is unavoidable and devise strategies to reduce its harmful effects
Adaptation
How can we reduce the threat?
We can improve energy efficiency, rely more on carbon-free renewable energy resources, and find ways to keep much of the co2 we produce out of the troposphere
What can the government do?
Tax greenhouse gas emissions and energy use, increase subsidies ad tax breaks for saving energy, and decrease subsidies and tax breaks for fossil fuels
A 2006 poll showed that how many (percentage) Americans want more leadership from federal government on dealing with global warming?
83 percent
The treaty on global warmings first phase went into effect when and with how many countries participating?
January 2005 and 189 countries
Requires how many participating developed countries to cut their emissions of co2, ch4, and n2o to 5.2 percent below their 1990 levels by 2012?
5.2%
Developing countries were excluded
- the us did not sign but California and Maine are participating
- us did not sign because china, India and brazil were excluded
In 2005 the EU
Proposed a plan to reduce co2 levels by 1/3rd by 2020
What state has adopted a goal of reducing its greenhouse gas emission to 1990 levels by 2020 and 80 percent below by 2050?
California
What companies have established targets to reduce their greenhouse emissions 10-65 percent to 1990 levels by 2010?
BP, IBM, and Toyota
What can you do?
- drive a fuel efficient car, walk, bike, carpool, and use mass transit
- use energy efficient windows
- use energy efficient appliances and lights
- heavily insulate your house and seal all drafts
- reduce garbage by recycling and reuse
- insulate your hot water heater
- use compact fluorescent bulbs
- plant trees to shade your house during the summer
- set water water no higher than 49 degrees Celsius
- wash laundry in warm or cold water
- use low flow shower head
- buy products from companies that are trying to reduce their impact on climate
- demand that the government make climate change an urgent priority
Less ozone in the stratosphere allows?
More harmful UV radiation to reach the earths surface
The ozone layer keeps what percentage of the suns harmful UV radiations from reaching the earths surface?
95 percent
What has lowered the average concentrations of ozone in the stratosphere?
CFCs
In what year were CFCs no longer manufactured?
1988
Ozone depletion in the stratosphere
During four months of each year up to half of the ozone in the stratosphere over Antarctica and a smaller amount over the arctic is depleted
Caused by CFCs and other ozone depleting chemicals (ODCs)
Ozone thinning
Increased UV radiation reaching the earths surface from ozone depletion is harmful to
Human health, crops, forests, animals, and materials such as plastic and paints
Effects of ozone depletion on human health
- worse sunburn
- more eye cataracts
- more skin cancers
- immune system suppression
Effects of ozone depletion on food and forests
- reduced yields for some crops
- reduced seafood supplies from reduced phytoplankton
- decreased forest productivity for UV sensitive tree species
Effects of ozone depletion on wildlife
- increased eye cataracts in some species
- decreased population of aquatic species sensitive to UV radiation
- reduced population of surface phytoplankton
- disrupted aquatic food webs from reduced phytoplankton
Effects of ozone depletion on air pollution and materials
- increased acid deposition
- increased photochemical smog
- degradation of outdoor paints and plastics
Effects of ozone depletion on global warming
*accelerated warming because of decreased ocean uptake of co2 from atmosphere by phytoplankton and CFCs acting as greenhouse gases
To reduce ozone depletion we must stop what?
Producing all ozone depleting chemicals
