geog 101: d ay 16 air pollution (cont’d); climate change the spittelau incineration plant in...
Post on 23-Dec-2015
214 Views
Preview:
TRANSCRIPT
GEOG 101: DAY 16Air Pollution (cont’d); Climate Change
The Spittelau incineration plant in Vienna, Austria, designed by Friedensreich Hundertwasser.
HOUSEKEEPING ITEMS
Consumer diesel vehicles are much cleaner in terms of particle emissions (PM-10 and PM-2.5), but big freight trucks and the like are still dirty.
Incinerator technology varies in its effectiveness. Wikipedia has a good description of the pros and cons and challenges of waste-to-energy and incineration: http://en.wikipedia.org/wiki/Incineration
Mercury is partly introduced into the environment by humans, but it is also there naturally, leaches out and bioaccumulates.
LCAs are due today if you did one. Check out the notes on-line, as I had a rare
opportunity to show you a very interesting video today that pulls a lot of threads we’ve been discussing together and also touches on climate change.
ACID DEPOSITION IS ANOTHER TRANSBOUNDARY POLLUTION PROBLEM
Acidic deposition = the deposition of acid, or acid-forming pollutants, from the atmosphere onto Earth’s surface Acid rain = precipitation of acid Atmospheric deposition = the wet or dry
deposition on land of pollutants Originates from burning fossil fuels
release sulfur dioxide and nitrogen oxides react with water to form sulfuric and nitric acids
14-3
SOURCES OF ACID DEPOSITION 14-4
ACID DEPOSITION IS ANOTHER TRANSBOUNDARY POLLUTION PROBLEM (CONT’D)
Rain and other forms of precipitation with pH of less than 5.1 are considered acidified
Acidic deposition can have wide-ranging, cumulative detrimental effects on ecosystems and on our built environmentAcids leach nutrients from the topsoilAlters soil chemistry harming plants Mobilizes toxic metal ionsRun-off into surface watersErodes and corrodes built structures (Parthenon)
14-5
ACID DEPOSITION HAS NOT BEEN REDUCED AS MUCH AS SCIENTISTS HAD HOPED
New technologies such as scrubbers have helped SO2 emissions are lower NOx emissions are higher Acid deposition’s effects are worse than predicted
14-6
INDOOR AIR POLLUTION
14-8
14-9
INDOOR AIR POLLUTION
Indoor air contains higher concentrations of pollutants than outdoor air
6,000 people in North America die per day from indoor air pollution
The average person in North America is indoors at least 90% of the time
Exposed to synthetic materials (insecticides, cleaning fluids, plastics, and chemically treated wood)
1973-74: ventilation systems were sealed off and windows put in that did not open, trapping pollutants inside
14-10
INDOOR AIR POLLUTION IN THE DEVELOPING WORLD ARISES FROM FUELWOOD BURNING
Burning wood, charcoal, dung, crop wastes for cooking and eating Kills 1.6 million people each year Causes pneumonia, bronchitis, allergies, cataracts,
asthma, heart disease, cancer and premature death
14-11
TOBACCO SMOKE AND RADON ARE THE MOST DANGEROUS INDOOR POLLUTANTS IN THE DEVELOPED WORLD
Secondhand smoke from cigarettes is especially dangerous Containing over 4000 dangerous chemicalsCauses eye, nose, and throat irritationSmoking has declined in developed nations
After cigarette smoke, radon gas is the second-leading cause of lung cancer in the developed worldColourless, odourless gas that can seep into buildings
14-12
MANY VOCS POLLUTE INDOOR AIR
VOCs = volatile organic compounds Released by everything from plastics and oils to
perfumes and paints Most VOCs are released in very small amounts Unclear health implications due to low
concentrations Also include pesticides, which are found indoors
more often than outdoors due to seepage Formaldehyde, which leaks from pressed wood
and insulation, irritates mucous membranes and induces skin allergies
14-13
14-14
LIVING ORGANISMS CAN POLLUTE INDOORS
Tiny living organisms can also pollute Includes dust mites and animal dander worsen
asthma Fungi, mold, mildew, airborne bacteria cause severe
allergies, asthma, and other respiratory ailments Sick building syndrome = a sickness produced
by indoor pollution with general and nonspecific symptoms Solved by using low-toxicity building materials and good
ventilation
14-15
LIVING ORGANISMS CAN POLLUTE INDOOR SPACES
Dust mites and animal dander Fungi, mould, and mildew Airborne bacteria (Legionnaire’s disease) Microbes that induce allergic responses are thought
to be a major cause of sickness produced by indoor pollution Sick-building syndrome
HOW SAFE IS YOUR INDOOR ENVIRONMENT?
Think about the amount of time you spend indoors. Name the potential indoor air quality hazards in your home, work, or school environment.
What could you do to make the indoor spaces you use safer?
14-16
weighing
the issues
14-17
WE CAN REDUCE INDOOR AIR POLLUTION
In developed countries:Use low-toxicity materials (there
are stores and brands that specialize in this now)
Monitor air qualityKeep rooms cleanLimit exposure to chemicals
In developing countries:Dry wood before burningCook outside (including with
solar cookers)Use less-polluting fuels (natural
gas)
CONCLUSION
Indoor air pollution is a potentially serious health threat
Outdoor air pollution has been addressed by government legislation and regulation in developed countries, but is still a problem
Improvement is required in reducing acidic deposition, photochemical smog
Avoiding unhealthy pollutants in developing world will pose a challenge as less-wealthy nations industrialize; indeed air pollution is getting worse
14-18
© 2010 Pearson Education Canada
15Global Climate Change
PowerPoint® Slides prepared by Stephen Turnbull
Copyright © 2013 Pearson Canada Inc.
15-19
Final exam will be Thursday, December 4th in the Gym
HOUSEKEEPING ITEMS
A couple of links on Vancouver Island’s ocean acidification problem: http://www.vancouversun.com/life/Acidic+water+blamed+West+Coast+scallop/9550861/story.html and http://www.cbc.ca/news/canada/british-columbia/acidic-ocean-deadly-for-vancouver-island-scallop-industry-1.2551662.
Check out the following film: www.filmsforaction.org/watch/wake_up_freak_out_then_get_a_grip/.
UPON SUCCESSFULLY COMPLETING THIS CHAPTER, YOU WILL BE ABLE TO
Describe Earth’s climate system and explain the many factors influencing global climate change
Characterize human influences on the atmosphere and global climate
Summarize modern methods of climate research Outline current and future trends and impacts of
global climate change Suggest ways we can respond to climate change
15-21
CENTRAL CASE: THE RETREAT OF THE ATHABASCA
The Athabasca Glacier has been retreating since 1844
Since then, it has lost half of its volume Currently retreating at a rate of 2-3 metres per year Is it retreating due to climate change or is it just a
natural continuation of the retreat of glacial ice that began 12,000 years ago?
The Rockies may be ice-free by the end of this century
“We’re in a giant car heading towards a brick wall and everyone’s arguing over where they’re going to sit.”
– David Suzuki
15-22
OUR DYNAMIC CLIMATE
15-23
OUR DYNAMIC CLIMATE
Climate influences everything around us The Fourth Assessment Report of the
Intergovernmental Panel on Climate Change (IPCC) made it clear that: Climate is changing, we are the cause, and this
change is already exerting impacts that will become increasingly severe if we do not take action
The Fifth is now out. Climate change is the fastest-moving area of
environmental science today, and the Fifth Report is now out and is even more urgent in its assessment and recommendations. Scientists, normally mere observers, are saying action has to happen now!
15-24
WHAT IS CLIMATE CHANGE?
Climate = an area’s long-term atmospheric conditionsTemperature, moisture content, wind, precipitation,
etc. Weather = conditions at localized sites over hours or
days Global climate change = describes trends and
variations in Earth’s climateTemperature, precipitation, storm frequency
Global warming = an increase in Earth’s average temperatureEarth’s climate has varied naturally through timeThe rapid climatic changes taking place now are due
to human activity: fossil fuels, combustion, and deforestation
15-25
THE SUN AND ATMOSPHERE KEEP EARTH WARM Four factors exert more influence on climate
than all others: The Sun (supplies planet’s energy) The atmosphere (absorbs 70% of incoming solar
radiation) The oceans (shape climate by storing and
transporting heat and moisture) Albedo = reflectivity of a surface (positive feedback
cycle of melting polar ice caps and ice sheets)
15-26
OUR PLANET ABSORBS SOLAR RADIATION (SOLAR BUDGET)
15-27
GREENHOUSE GASES WARM THE LOWER ATMOSPHERE As Earth’s surface absorbs solar radiation, the
surface increases in temperature and emits infrared radiation (for a good description overall, see NASA’s site: http://missionscience.nasa.gov/ems/13_radiationbudget.html.)
Greenhouse gases = atmospheric gases that absorb infrared radiation (radiatively active gases) Water vapor, ozone, carbon dioxide, nitrous oxide,
methane, chlorofluorocarbons (CFCs) Greenhouse gases differ in their ability to warm the
troposphere and surface
15-28
GREENHOUSE GASES WARM THE LOWER ATMOSPHERE (CONT’D)
After absorbing radiation, greenhouse gases re-emit infrared energy Some energy is lost to space Greenhouse effect = some energy travels back
downward, warming the troposphere and the planet’s surface
Global warming potential = the relative ability of one molecule of a given greenhouse gas to contribute to warming Expressed in relation to carbon dioxide (potential =
1) Nitrous oxide is 296 times as potent as carbon
dioxide
15-29
CARBON DIOXIDE IS THE ANTHROPOGENIC GREENHOUSE GAS OF PRIMARY CONCERN
Not the most potent greenhouse gas, but it is extremely abundant The major contributor to global
warming Human activities have boosted
atmospheric concentrations from 280 parts per million (ppm) to 389 ppm in 2010 (and now over 400)
15-30
HUMAN ACTIVITY HAS RELEASED CARBON FROM SEQUESTRATION IN LONG-TERM RESERVOIRS
Human activities accelerate the fluxes of material from one reservoir to another in biogeochemical cycles Burning fossil fuels transfers CO2 from lithospheric
reservoirs into the atmosphere Deforestation transfers CO2 from terrestrial reservoirs
into the atmosphere Sinks = reservoirs that accept more of the material
than they release Ocean
15-31
OTHER GREENHOUSE GASES CONTRIBUTE TO WARMING
Methane from fossil fuel deposits, livestock, landfills, and crops such as rice
Nitrous oxide from feedlots, chemical manufacturing plants, auto emissions, and synthetic nitrogen fertilizers
Ozone from photochemical smog Halocarbons (CFCs and HFCs) Water vapor = the most abundant greenhouse
gas and contributes most to the greenhouse effect
15-32
THERE ARE MANY FEEDBACK CYCLES IN THE CLIMATE SYSTEM
Positive feedback cycle Warming leads to water vapour which leads to further
warming causing still more evaporation, and so on Negative feedback cycle
Warming leads to evaporation which leads to water vapour causing increased cloudiness slowing global warming
Aerosols = microscopic droplets and particles that have either a warming or cooling effect
15-33
RADIATIVE FORCING EXPRESSES CHANGE IN ENERGY INPUT OVER TIME
Radiative forcing = the amount of change in energy that a given factor causes Positive forcing warms
the surface; negative forcing cools it
Compared with the pre-industrial Earth, Earth is experiencing radiative forcing of 1.6 watts/m2
Enough to alter the climate
15-34
THE ATMOSPHERE IS NOT THE ONLY FACTOR THAT INFLUENCES CLIMATE Milankovitch cycles = periodic changes in
Earth’s rotation and orbit around the Sun Solar output = drives temperature change on
Earth’s surface Ocean absorption = the ocean holds 50 times
more carbon than the atmosphere and absorbs it from the atmosphere (acts as a sink)
Ocean circulation = ocean water exchanges tremendous amounts of heat with the atmosphere, and ocean currents move energy from place to place Thermohaline circulation
15-35
IN ATLANTIC, WARMER SURFACE WATER FLOWS NORTH (E.G. THE GULF CURRENT), COOLS AND SINKS, FORMING THE NORTH ATLANTIC DEEP WATER (NADW)
15-36
THE SCIENCE OF CLIMATE CHANGE
15-37
• Proxy indicators = types of indirect evidence that serve as substitutes for direct measurements
- Ice caps, ice sheets, and glaciers hold clues to past climate
- Trapped bubbles in ice cores show atmospheric composition, greenhouse gas concentration, temperature trends, snowfall, solar activity, and frequency of fires
Proxy indicators tell us about the past
15-38
DIRECT ATMOSPHERIC SAMPLING TELLS US ABOUT THE PRESENT
Atmospheric carbon dioxide concentrations have increased from 315 ppm in 1958 to 401 ppm in 2013
There are seasonal variations in levels due to photosynthetic uptake More carbon dioxide absorbed during northern
summer
15-39
MODELS HELP US UNDERSTAND CLIMATE
Climate models simulate climate processes
Use information about: atmospheric
circulation ocean circulation interactions feedback
mechanisms
15-40
MODELS HELP US UNDERSTAND CLIMATE (CONT’D)
15-41
• Effectiveness of models are tested by entering data from the past and running the model toward the present
CURRENT AND FUTURE TRENDS AND IMPACTS
15-42
CURRENT AND FUTURE TRENDS AND IMPACTS
Evidence that climate conditions have changed since industrialization is now overwhelming and indisputable
The way each of us experiences these impacts will vary tremendously
The impacts on Canada could be particularly severe, depending on where we live, though it should be pointed out that other nations have already been harder hit – the Maldives, Bangladesh, Australia, even parts of the U.S.
15-43
THE IPCC SUMMARIZES EVIDENCE OF CLIMATE CHANGE AND PREDICTS FUTURE IMPACTSTrend = a pattern that persists within a data set,
even after short-term fluctuations and anomalies have been accounted for
Intergovernmental Panel on Climate Change (IPCC) 2013: Fifth Assessment Report
Consensus of scientific climate research from around the world
Trends in surface temperature, precipitation patterns, snow and ice cover, sea levels, storm intensity, and other factors
15-44
TEMPERATURE INCREASES WILL CONTINUE
The IPCC report concludes that average surface temperatures on earth have been rising since 1906, with most of the increase occurring in the last few decades (0.74 R C)
Fifteen years from 1997-2011 among the 20 warmest years on record
Permafrost = perennially frozen ground Thawing in the ArcticPotentially releasing methane
15-45
PROJECTED INCREASES IN SURFACE TEMPERATURE
More frequent heat waves Temperature change will vary by
region Stronger storms
15-47
Kyoto successes (blue) and failures (red) – including the effects of land use – see The Guardian: (this was the web site I was looking for)http://www.theguardian.com/environment/blog/2012/nov/26/kyoto-protocol-carbon-emissions
CLIMATE CHANGE AND HUMAN RIGHTS
In December 2005, a group representing North America’s Inuit sent a legal petition to the Inter-American Commission on Human Rights, demanding that the United States restrict its greenhouse gas emissions, which the Inuit maintained were destroying their way of life in the Arctic. After a year, the commission dismissed the petition with a terse three-sentence letter. Do you think Arctic-living people deserve compensation from industrialized nations whose emissions have caused climate change that has disproportionately affected the Arctic? Do you think climate change can be viewed as a human rights issue? What ethical issues, if any, do you think climate change presents? How could these best be resolved?
weighing
the issues
15-50
CHANGES IN PRECIPITATION WILL VARY BY REGION
Some regions are receiving more precipitation than usual, and others are receiving less
Droughts have become more frequent and severe (e.g. California and Australia) Harming agriculture, promoting soil erosion, reducing
drinking water supplies, and encouraging forest fires Heavy rains have contributed to flooding (UK and
Bangladesh)
15-51
PROJECTED CHANGES IN JUNE-AUGUST PRECIPITATION, 2090-2099
15-52
MELTING ICE AND SNOW HAVE FAR-REACHING EFFECTS Mountaintop glaciers are disappearing (“Glacier Park”
may soon become a misnomer) Have lost an average of 14 m since 1980 Risks of sudden floods as ice dams burst Reducing summertime water supplies
As ice melts, darker, less-reflective surfaces are exposed and absorb more sunlight, causing more melting
Melting permafrost makes slopes unstable and could release soil gases leading to further warming
15-53
THE ARCTIC IS CHANGING DRAMATICALLY
Less snow cover Melting immense ice sheets (Greenland ice sheet):
http://earthsky.org/earth/video-largest-glacier-calving-ever-caught-on-film
Canada’s ice shelves have shrunk by 90% over the past 100 years (Ayles Ice Shelf)
Warming is accelerating as snow and ice melt, darker, less-reflective surfaces are
exposed Earth’s capacity to reflect light decreases
15-54
RISING SEA LEVELS WILL AFFECT HUNDREDS OF MILLIONS OF PEOPLE AND COASTAL ZONES
As glaciers and ice melt, increased water will flow into the oceans
As oceans warm, they expand
See “Island President” (film)
15-55
AN ICE-FREE NORTHWEST PASSAGE AND CANADA’S ARCTIC SOVEREIGNTY
Now that the Northwest Passage – the long-coveted sea route from the Atlantic to the Pacific via the Arctic Ocean – may soon be ice-free, northern nations are anxious to confirm its sovereignty over Arctic waters at an international conference held in Greenland recently, and Prime Minister Stephen Harper pledged to spend billions of dollars defending Canada’s interests in the Arctic if necessary. In addition to the sea route, the Arctic subsurface may hold as much as 25% of the world’s undiscovered oil and gas reserves.
The U.S. argues that the High Arctic does not belong to Canada, or to anyone else. What do you think? Who should control Arctic Ocean waters, and for what purposes? How much of Canadian taxpayers’ money should be spent to assert and maintain Canada’s sovereignty in the Arctic?
weighing
the issues
15-56
CLIMATE CHANGE AFFECTS ORGANISMS AND ECOSYSTEMS
Global warming modifies temperature-dependent phenomenaTiming of migration, breeding
Spatial shifts in the range of organismsAnimals and plants will move towards the poles
or upward in elevation20-30% of all species will be threatened with
extinction Plants act as carbon sinks; fewer plants means
more CO2 in the atmosphere
15-57
ENVIRONMENTAL REFUGEES?
The Pacific island nation of Tuvalu has been losing 9 cm of elevation per decade to rising seas. Appeals from Tuvalu’s 11,000 citizens were heard by New Zealand, which began accepting them in small numbers as of 2003, although the government has not officially categorized them as environmental refugees – people driven from their homelands as a result of environmental change or natural disaster. Tuvaluans have been particularly vocal about global warming, but several other small Pacific island nations have joined in voicing their concerns.
Will there come a time when neighbouring countries should begin to treat people who leave small island nations as environmental refugees? Should they be doing it now? What will happen to these people after relocation – do you think a national culture can survive if its entire population is relocated?
weighing
the issues
15-58
CLIMATE CHANGE EXERTS SOCIETAL IMPACTS – AND VICE VERSA
Agriculture: growing seasons shortened, crops more susceptible; crop
production will decrease, worsening hunger Forestry:
increased insect and disease outbreaks, increased chance of forest fires (pine beetle larvae used to be killed by colder winter temperatures)
15-59
CLIMATE CHANGE EXERTS SOCIETAL IMPACTS – AND VICE VERSA (CONT’D)
Health: heat waves can cause death, respiratory ailments,
expansion of tropical diseases, increased chance of drowning if storms become intense, hunger-related ailments
Economics: some costs and some benefits; costs will outweigh the
benefits, widen the gap between rich and poor, will cost roughly 5-20% of world GDP
15-60
ARE WE RESPONSIBLE FOR CLIMATE CHANGE?
The IPCC concluded:It is more than 90% likely that most of the
global warming recorded over the past 50 years is due to the well-documented increase in greenhouse gas concentrations in our atmosphere
Today the debate concerning the human role in climate change is largely over
Shift in public perception Role of Al Gore’s 2006 “An Inconvenient Truth”
15-61
RESPONDING TO CLIMATE CHANGE
15-62
RESPONDING TO CLIMATE CHANGE
We will likely either keeping on pursuing economic growth at all costs, which will require more and more resources to fix the damage (what ecological economists call ‘dis-economies of scale’), and will eventually lead to social, economic, and population crash, or
We will make sustainability our first priority, aim for a ‘soft landing’ and create a steady-state economy.
Is this even possible? It’s like going from believing the Earth is flat to believing that it is round.
15-63
SHALL WE PURSUE MITIGATION OR ADAPTATION, OR INTERVENTION?
Mitigation = pursue actions that reduce greenhouse gas emissions, in order to lessen severity of future climate change Renewable energy sources, farm practices to protect
soil integrity, preventing deforestation
Adaptation = accept climate change is happening and pursue strategies to minimize its impacts on us Criticized as sidestepping
Both are necessary
15-64
SHALL WE PURSUE MITIGATION OR ADAPTATION, OR INTERVENTION? Intervention = set of possible large-scale
technological modifications to the global climate system
Causes of concern: Interfering with global-scale Earth’s systemsAbandon mitigation efforts
Geo-engineering – grand scale intervention (for more information, see http://www.scientificamerican.com/article/geoengineering-to-save-the-world-from-global-warming/ and other sources in Google Increase fluxes of greenhouse gasesReduce incoming solar radiation
15-65
WE CAN LOOK MORE CLOSELY AT OUR LIFESTYLE
Conservation and efficiency High-efficiency light bulbs and appliances Reduce electricity consumption Life-style choices
Sources of electricity Alter types of energy we use Natural gas cleaner than oil; oil cleaner than coal
Carbon capture and storage = remove CO2 from power plant emissions
Other?
15-66
TRANSPORTATION IS A SIGNIFICANT SOURCE OF GREENHOUSE GASES; LIKEWISE BUILDINGS
Automotive technology• make vehicles more fuel-efficient, hybrid cars
Driving less and using public transportation Public transportation is the most effective way to
conserve energy, reduce pollution Live nearer your workplace, so you can bike or walk
(http://www.walkscore.com/)
15-67
CONVENTIONAL CARS ARE EXTREMELY INEFFICIENT
15-68
WE CAN REDUCE EMISSIONS IN OTHER WAYS AS WELL Use advances in agriculture, forestry, and waste
management Grow renewable biofuels (or produce from waste
vegetable oil) Rapid reforestation of deforested areas Recovering methane from landfills Recycling, composting, and reduction or reuse of
materials
15-69
WE WILL NEED TO FOLLOW MULTIPLE STRATEGIES TO REDUCE EMISSIONS
There is no single ‘magic bullet’ for mitigating climate change
Most reductions can be achieved using current technology so we can begin right away
How quickly and successfully we translate science and technology into practical solutions for reducing emissions depends on policies and the market economy or, one might argue, taming the market economy and the corporations that dominate it – especially the oil companies
15-70
WE BEGAN TACKLING CLIMATE CHANGE BY INTERNATIONAL TREATY
UN Framework Convention on Climate Change (FCCC) = outlines a plan for reducing greenhouse gas emissions to 1990 levels by the year 2000 through a voluntary, nation-by-nation approach By the late 1990s, it was clear that the voluntary
approach would not succeed (few met their targets)
Developing nations created a binding international treaty that would require all signatory nations to reduce their emissions
However, subsequent rounds of talks have proven relatively fruitless (“prisoner’s dilemma”)
15-71
It’s curious the Danes would be amongst the failing nations – they lead the world in wind energy, and they ride more bicycles per capita than anyone else!?
WE BEGAN TACKLING CLIMATE CHANGE BY INTERNATIONAL TREATY (CONT’D)
The Kyoto Protocol by 2012 nations were to reduce emissions of six
greenhouse gases to levels below those of 1990 took effect in 2005, after Russia became the 127th nation
to ratify it; Canada withdrew in 2011 The United States will not ratify the Kyoto Protocol
Did not require same of countries of China and India Businesses in industrialized nations feel they have
more to lose economically from restrictions
15-73
Carbon taxes (e.g., B.C. – since weakened) Permit trading programs
harness the economic efficiency of the free market to achieve policy goals
The Chicago Climate Exchange is the world’s first emissions trading program for greenhouse gas reduction
Cap-and-trade programs European Union Emission Trading Scheme
Market mechanisms are being used to address climate change
15-74
CARBON OFFSETS ARE IN VOGUE
Carbon offset = a voluntary payment to another entity intended to enable that entity to reduce the greenhouse emissions that one is unable or unwilling to reduce oneself Popular among utilities, businesses, universities,
governments, and individuals trying to achieve carbon neutrality
Carbon-neutrality = no net carbon is emitted, as with certain housings, buildings, and developments
Carbon offsets fall short A lack of oversight to make sure that the offset
money accomplishes what it is intended for
15-75
YOU CAN REDUCE YOUR OWN CARBON FOOTPRINT
Carbon footprint = expresses the amount of carbon we are responsible for emitting (see How Bad Are Bananas? The Carbon Footprint of Everything by Mike Berners-Lee). To calculate yours, see http://cotap.org/carbon-footprint-calculator/.
What do you think you can do to make a difference? What about in relation to politicians and
corporations? Global climate change may be the biggest
challenge facing us and our children Taking immediate action is the most important
thing we can do
15-76
CONCLUSION
Many factors influence Earth’s climateHuman activities play a major role
Climate change is well underwayFurther emissions will cause severe and diverse
impacts More and more scientists are urging immediate
actionReducing emissionsMitigating and adapting to a changing climate
15-77
top related