APES UNIT 9 TEST (THE REAL VERSION)
Other CFC Sources
- Aerosol Propellants - Commercial and Residential Refrigeration and Air Conditioning - Solvent Cleaning of Metal and Electronic Parts - Mobile Air Conditioners
Carbon Dioxide and Temperature Records
- Atmospheric concentration of CO2 plays a key role in determining the average temperature of the atmosphere - Measurements of CO2 in bubbles at various depths in ancient glacial ice indicate changes in levels of CO2 in the lower atmosphere correlate closely with changes in global average temperature near the earth's surface during the past 4000,000 years. - Atmospheric CO2 level has increased dramatically over time and is much higher today than it was thousands of years ago - The industrial revolution has caused a dramatic rise in CO2 - At the time of the industrial revolution, CO2 concentration was approximately 288 ppm.
Polar Ice Melting
- Both land and sea ice are of concern - Ice has high albedo so it reflects a lot of the sun's radiation - The globe is getting warmer sand the ice is melting and revealing either land or water, which has a lower albedo thus absorbing more of the heat rather than reflecting it and causing more ice to melt (positive feedback loop) - Changes albedo of poles creating positive feedback loop warming those areas
Anthropogenic Sources that Contribute to Greenhouse Gas Emissions
- Burning Fossil Fuels - Deforestation/Land use Changes - Livestock Fermentation (methane release) and waste management - Methane release associated with rice paddies - Use of CFC's/HFC's in products such as refrigeration systems, air conditioning, and manufacturing - Use of fertilizers
Sea Level Rise
- Can be positive: newly created habitats on flooded continental shelves - Can be negative: deeper communities may no longer have adequate access to sunlight for photosynthesis - Causes Land Ice (ex: continental glaciers, ice sheets-not the same as sea ice) to melt, adding to the volume of water in the ocean - Causes thermal expansion of the ocean, due to warming from climate change increasing the volume of the ocean - Causes human and organism community displacement - Pushes estuaries back - Plants like mangroves will be found further inland - Reduction of light availability and decreasing temperature can lead to conditions out of the range of tolerance for some organisms, like coral reefs which can lead to coral bleaching - Increasing depth of the ocean impacts organisms that will no longer be in the photic zone
Effects of Ocean Warming as a Result of Climate Change
- Can lead to a loss of habitat for marine species - Can alter metabolic rates (increase) for marine species - Can alter reproductive rates and sex ratios in certain species - Can cause coral bleaching/ loss of algae within corals - Can cause organisms such as fish to migrate toward the poles where water is cooler
Overview of Greenhouse Gasses
- Carbon Dioxide is the largest source of emissions - Fluorinated Gasses is the smallest source of emissions - Electricity and Transportation are the largest sectors of emissions - Agriculture is the smallest sector of emissions - Water Vapor is the most abundant greenhouse gas, but due to short time spent in atmosphere it doesn't contribute much to climate change - Atmosphere composition: 78% of atmosphere N2 (nitrogen), 21% Oxygen, 1% is greenhouse gasses
Global Climate Change
- Caused by excess greenhouse gasses in the atmosphere - Can lead to rising sea levels resulting from melting ice sheets, ocean water expansion, and disease vectors spreading from the tropics to the poles - Implications can lead to population dynamic change and movement in response - Climate - determined by weather conditions of the earth or of a particular area, especially atmospheric temperatures, averaged over at least three decades; data used to divide the earth into various climate zones - Only trend is that our climate is not fixed - Over the past 900,000 years the troposphere has undergone global warming and cooling - Causes sea level rise: terrestrial ice melts into ocean, and thermal expansion of ocean - Causes increased range for disease vectors - Impacts ecological populations - Impacts human populations, especially those already vulnerable to change
Changes in Air Circulation
- Changes in air temperature can change global air circulation like convection currents - The jet stream(one of the air patterns we see circumnavigate the globe) could change in speed and strength which would lead to changes in the type and intensity of global weather patterns
Greenhouse Gasses With A Global Warming Potential(GWP) Greater Than 1
- Chlorofluorocarbons (CFC's)/ Hydrofluorocarbons (HFC's) - Methane(CH4) - Ozone(O3) - Nitrous Oxide(N2O)
Kyoto Protocol
- Controlling global warming by setting greenhouse gas emissions targets for developed countries - An international treaty which extended the 1992 United Nations Framework Convention on Climate Change (UNFCCC) that commits state parties to reduce greenhouse gas emissions, based on the scientific consensus that global warming is occurring and that human-made CO2 emissions are driving it - Adopted in Kyoto, Japan, on 11 December 1997 and entered into force on 16 February 2005.
Antarctic Spring
- Depletes ozone
Sea Ice Melting
- Destroys polar bear habitat and preying method - The more sea ice that melts the less available food is for polar bears
Disease Vectors Expand Their Range
- Disease vectors are usually insects that like to live in tropical areas - When the globe heats up, their range will expand - Common Disease Vectors include: ticks, fleas, and mosquitos - Mosquitoes are vectors for Malaria, West Nile Virus, and Zika Virus
Most Common Cancers as a Result of UV Radiation
- Even one severe sunburn doubles your chance of getting squamous or basal cell skin cancers (not very concerning) - 3 or more blistering sunburns before age 20 makes you 5 times more likely to develop malignant melanoma, which can spread to other organs (very concerning)
Squamous Cell Carcinoma (SCC)
- Grows over months - May spread if not treated - Scaly red areas that may bleed easily - Ulcers or non bleeding sores that are often painful to the touch - Often found on ears, lips, scalps, back of the hands, and lower legs
Basal Cell Carcinoma (BCC)
- Grows slowly over months or years - Small, round, flat spots that are red, pale, or pearly in color - May look scaly like a patch of eczema - May become ulcerated, bleed, and fail to heal
Major Greenhouse Gasses
- H2O (Water) - CO2 (Carbon Dioxide) - CH4 (Methane) - N2O (Nitrous Oxide) - CFCs *only anthropogenic (man made) greenhouse gas*
Climate Change Impacts
- Habitat Destruction(terrestrial and marine) - Loss of food source - Timing of food source availability changes - New Temperatures beyond range of tolerance - New salinity beyond range of tolerance - Increased storm intensity - Increased possibility of fire - Impacted annual group behaviors: timing of migration, hibernation - Decrease soil quality
Factors that may lead to Extinction
- Habitat loss - Hunting - Poaching is illegal hunting for sale or profit - Animals can be hunted for food, prized body parts, traditional medicinal uses, medical research purposes, sport - Having a limited diet and habitat - Niche specialists are at greater risk of extinction - Being outcompeted by invasive species - Invasive = r-selective niche generalists that can outcompete k selective
Climate Change Impacts on Human Health
- Increase in spread of vector diseases has habitat moves from tropics to poles - Increase in algal blooms and waterborne diseases from increased water temperature - Increase in exposure to extreme heat and cold/ increase risk of illness and death from exposure to increased extreme temperatures - Increase in chronic conditions (cardiovascular disease, respiratory disease, etc.) from prolonged exposure to extreme temperatures
Soil Viability and Erosion
- Increased temperatures can dry out soils - Soil erosion due to increase in wind or water - Soil erosions and degradation most common in coastal areas
Permafrost Melting
- Not correlated to sea level rise - As globe gets warmer permafrost is melting and making undecayed organic matter wet - Causes anaerobic decomposition which produces methane that enhances warming cycle (positive feedback loop) - The earth continues to warm and melt more permafrost
Ocean Acidification
- Occurs when atmospheric carbon dioxide dissolves in seawater - Reacts with the water to form carbonic acid - Carbonic acid dissociates into its ions - Hydrogen ions produced by this disassociation increase acidity, lowering seawater pH Increased atmospheric carbon dioxide ultimately produces more hydrogen ions, lowering pH further
Natural Greenhouse Gas Effect
- Occurs when gasses in Earthś atmosphere trap the Sun's heat - Makes Earth warmer than it would be without an atmosphere - Warms the Earth's lower troposphere and surface - We also have a natural cooling process- large quantities of heat are absorbed by the evaporation of liquid surface water, and the water vapor molecules rise, condense to form droplets in clouds, and release their stored heat higher in the atmosphere - Amplified by excess greenhouse gasses in the atmosphere
Climate Change Impacts on Changing Ocean Currents
- Ocean conveyor belt is warm water surface flow and cooler water subsurface flow and changes based on salinity and temperature changes globally - Altered ocean currents can impact terrestrial climate especially in coastal areas - Salinity and temperature changes impact water density, which can impact the ocean conveyor belt
Causes of Ocean Warming
- Ocean warming is the global increase in ocean water temperatures - The amount of warming is not uniform across the globe, some areas have warmed quicker than others - Caused by increased greenhouse gasses in Earth's atmosphere, such as carbon dioxide and methane - Estimated that our oceans have absorbed 93% of the excess heat from greenhouse gas emissions since the 1970's
Trends of Ozone Due to Human Activities
- Ozone is the Earth's sunscreen - Filters out UV which allows life to exist and protects us from sunburn, skin, and eye cancer - If there is a decrease the beneficial ozone in the stratosphere then there is an increase in the harmful ozone in the troposphere (photochemical smog)
Ozone Depletion in the Stratosphere
- Ozone layer in the stratosphere keep about 95% of UV radiation from reaching surface of Earth - A hole (THINNING) has developed in the ozone layer as a result of CFC use
Montreal Protocol
- Phased out substances responsible for ozone depletion, starting in 1989 - Successfully phased out 98% of ozone depleting substances within 25 years - In 1987, 24 nations agreed on a protocol to reduce the use of substances depleting the ozone layer and to phase out the use of CFCs and other chemicals due to their depletion of the ozone layer by 1995 - In 2016 scientists discovered that the ozone layer is slowly healing, which means the Montreal Protocol is working, they also believe the Antarctic hole will completely heel by the 21st century (between 2030 and 2050)
The Problem With CFC's
- Remain in the troposphere because they are insoluble in water and chemically unreactive - These chemicals are lifted into the stratosphere by drift convection and mixing of air - Once they reach the stratosphere they break down into highly reactive Cl,Br, and I atoms which accelerate the breakdown of ozone - Each CFC molecule can last for 65-385 years in the stratosphere
Methane (CH4)
- Rice Paddies are largest source of Methane - Ocean and Fresh Water is the smallest source of Methane
Climate Change Impact on Marine Organisms
- Sea level rise can lead to a loss of habitat - Sea level rise can reduce the available light in marine habitats, thus reducing or eliminating primary productivity there - Melting land ice can decrease ocean salinity, putting the salinity beyond the range of tolerance for some organisms
Ozone(O3)
- Secondary pollutant Troposphere: - Lower Level (bad)- makes smog - Middle Level (good)- destroys pollutants - Upper Level (bad)- traps heats Stratosphere: - (good)- absorbs UV rays - Naturally exists - Antarctica winter create stratospheric ice crystals that contribute to ozone degradation and thinning the ozone layer
Chlorofluorocarbons (CFC's) and Hydrofluorocarbons (HFC's)
- Serves as refrigerant/coolant/propellant/components of some plastics - Can escape and enter stratosphere UV light removes Chlorine(Cl) from CFC's - free Chlorine catalyzes the conversion of O3 to O2 - Production of Plastic Foam and Foam Insulation Products is the largest source - Sterilization of Medical Equipment and Instruments is the smallest source - Chlorofluorocarbons and Hydrochlorofluorocarbons are fully or partly halogenated hydrocarbons that contain carbon, hydrogen, chlorine, and fluorine, produced as volatile derivatives of methane, ethane, and propane - Thought to be "dream" chemical - Inexpensive to produce - Ex: refrigerators and air conditioners (most common) coolant Halon - used by some aviation industries as a fire suppression system - coolant
Harmful Effects of UV Radiation
- Skin Cancer (ultraviolet radiation can destroy acids in DNA) - Cataracts and sun burning - Suppression of immune system - Adverse impact on crops and animals - Reduction in the growth of ocean phytoplankton - Degradation of paints and plastic material
Recent Greenhouse Gas Concentrations
- Spiking beyond previous historical maximum values
Nitrous Oxide (N2O)
- Synthetic Soil Fertilization is the largest source of Nitrous Oxide - Livestock Manure is the smallest source of Nitrous Oxide
Kiribati Profile
- The low lying Pacific island nation of Kiribati is threatened by rising sea levels - Some of its 32 coral atolls are already disappearing beneath the ocean - Elevation Extremes: High point- 266ft Low point- 0ft
Result of Too Much CO2 Absorption
- Then the ocean will experience a decrease in pH as more carbonic acid is made. - H2O + CO2 🡨🡪 H2CO3 (carbonic acid formation) - Carbonic acid easily dissociates into ions - H2CO3 🡨🡪 H+ + HCO3- (most common) - Acidic water can eat away at the calcium carbonate shells of organisms and coral reefs... - CaCO3 + 2H+ 🡪 Ca2+ + H2CO3
Effects of Ozone Depletion
- Thinning of poles, especially Antarctica, and antarctic spring - Disruption of terrestrial photosynthesis - Disruption of photosynthesis by phytoplankton - Disruption of food chain/webs - Impacts populations of some organisms like amphibians - Impacts human health: skin cancer, cataracts
Carbon Dioxide (CO2)
- Transportation and electricity are the largest and second largest source/contributor - Residential and Commercial is the smallest source/contributor - China has the highest CO2 Emissions from Consumption of Energy - South Korea has the lowest CO2 Emissions from Consumption of Energy
UV Rays
- UV-C is the strongest- 100% absorbed by ozone layer - Single chlorine atom removes about 100,000 ozone molecules
Key Factors in Past Climate Change
- Volcanic eruptions and impacts by meteors and asteroids - cool earth by injecting large amounts of debris in atmosphere - Changes in solar input (sunspots, solar flares, corona loops and coronal mass ejections)- warm or cool Milankovitch cycles: - Eccentricity -slight changes in shape of earth's orbit around sun - mostly round to more elliptical over a 100.000 cycle - Obliquity - slight changes in tilt of earth's axis over 41,000 year cycle - Precession - slight changes in the earth's wobbly orbit around the sun over a 19-26,000 year cycle - Global air circulation patterns - Changes in sizes of areas of ice that reflect incoming solar energy and cool the atmosphere - Changes in concentrations of greenhouse gasses - Occasional changes in ocean currents
Recent Temperature Changes
- Warmer temperatures are starting to approach and exceed the maximum values that we have seen for the past 800,000 years - Earth is warming which is correlated with an increase in greenhouse gas concentrations
Stresses Linked to Coral Bleaching Events
- Warmer/Colder than normal water temperatures - Nutrient pollution from runoff - Overfishing - Tourism Industry - Changes in Salinity - Dredging Turbidity
Melanoma
- Warning Sign: Asymmetry, ragged border, color variation, diameter larger than pencil eraser - Accounts for 1-2 percent of all skin cancers - MOST dangerous and aggressive form of skin cancer - If left untreated can spread to other body parts and become fatal - Grows quickly over weeks to months - Occurs in younger and older generations - Can appear as a new or existing spot, freckle, or mole that changes color, size, or shape - Can grow anywhere on the body not just parts exposed to the sun - Occurs most frequently on the trunk of males and the arms and legs of females - Can appear as a lump, with little or no brown pigment, as a reddish patch, or like a blood blister
Effects of Ocean Acidification
- When calcium carbonate is undersaturated in seawater, organisms such as clams, oysters, and crustaceans shells can start dissolving - Can alter signaling molecules which could in turn have potentially detrimental effects on a number of different marine species who use signals for detecting predators, settlement, and reproduction
which of the following is a method for mitigating the effects of climate change?
- carbon capture and storage in underground geological features - sequestering carbon in trees - geoengineering the ocean with iron seeds to encourage algae to absorb carbon - improving fuel efficiency to reduce fossil fuel use
Weather
- consists of short-term changes in atmospheric variables such as the temperature and precipitation in a given area over a period of hours or days
Why is the bleaching of coral reefs a great concern?
- corals provide habitats for 25% of all marine life - coral reefs protect the shores from storm waves - coral reefs provide tourist attractions - coral reefs support the fishing industry
Melting Permafrost
- increases anaerobic respiration (decomposition) = methane gas production increases
What is a possible impact of climate change?
- sea levels rising - spread of tropical diseases - ocean acidification - rise in the number of environmental refugees - ocean temperatures increasing
What plays a role in climate change?
- vehicle emissions - power plant emissions - deforestation - raising large herds of livestock
Which of these is a cause of coral bleaching?
- warming of ocean temperatures - increased turbidity of the water - runoff of nutrients from farms into the water
Approximately what percent of the heat from the sun is absorbed by the atmosphere and clouds?
20%
How much concentration of CO2 is in the atmosphere in ppm?
412.5 ppm
Approximately what percent of the heat from the sun is reabsorbed by the Earth?
50%
Negative Feedback Loop
A feedback loop in which a system responds to a change by returning to its original state, or by decreasing the rate at which the change is occurring.
Prehistoric Climate Forensics
Air bubbles trapped in ice cores, and ocean/lake sediment cores are analyzed to uncover information about past: - temperature trends - greenhouse gas concentrations - snowfall - forest fire frequency - Volcanic ash -Iceland core - Calcium carbonate foraminifera exoskeletons are analyzed to determine - Carbon (12C or 13C) used to determine age (carbon-12 preferred by plants) - Amount of oxygen in shells used to determine temperature - the oxygen isotope they take up in their shells varies with temperature (18O or 16O locked in glaciers, when glaciers melt and precipitates back on earth, concentration increases ) - In polar regions we can drill into ice and pull out an ice cylinder and analyze the air from air bubbles and dark lines tell about different melting times which tells us about warming and cooling and the concentration of gasses in the atmosphere - We can also use volcanic ash to determine info - Historical data shows that the Earth has gone through periods of warming and cooling correlated to rises and falls in greenhouse gas levels, shown by ice cores
3 Main Types of Skin Cancer
Basal Cell Carcinoma, Squamous Cell Carcinoma, Melanoma
Major sources include aerosols and leaking refrigerators
CFC
which greenhouse gas ONLY comes from anthropogenic sources?
CFCs
Major sources include rice paddies and landfills
CH4
melting permafrost will release large amounts of which major greenhouse gas into the atmosphere?
CH4 (methane)
Which greenhouse gas do human activities produce the most of?
CO2
Which greenhouse gas remains in the troposphere the longest amount of time?
CO2
Other Tropospheric Temperature Mediators
Clouds: - Warming effect: clouds absorb and release heat into the troposphere - Cooling effect: by reflecting more sunlight back into space - Particulates(ash, sand, dust): - Can increase cloud cover (can be natural or man made). - Some have a high albedo and reflect more incoming sunlight back into space during the day. - Will keep day time temps COOLER as sunlight reflected out - BUT nights become warmer because heat cannot be radiated back into space. Albedo(how much sun something reflects): - A measure of surface reflectivity - It is the ratio of sunlight reflected by a surface to the amount absorbed. - Surface without snow or ice absorbs more heat - Surface with snow and ice reflects more heat - White has a higher albedo than black surfaces
Large volcanic eruptions have what affect on global temperatures?
Cools Earth by injecting large amounts of debris in the atmosphere
What is true about the Kyoto Protocol
Developed nations required to reduce CO2, CH4, and NO2 emissions.
Climate Change Impacts on Human Population (populations at highest risk)
Due to Exposure: - Low Income Populations - Occupational Groups - People in Certain Locations Due to Sensitivity: - Pregnant Women - People with Pre-Existing Medical Conditions - Children Due to Ability to Adapt: - Older Adults - People with Disabilities - Indigenous People
Which of the following does not play a role in global climate change?
El Nino
The graph above shows CO2 measurements taken from Mauna Loa, Hawaii, and the Vostok ice core, which was drilled from ice sheets in Antarctica. Based on the data shown in the graph, which of the following is the most plausible hypothesis about the number of glacial periods that occurred in the past 400,000 years?
Four glacial periods occurred in the past 400,000 years.
damming rivers causes excessive evaporation of this
H2O
The graph above shows CO2 measurements taken from Mauna Loa, Hawaii, and the Vostok ice core, which was drilled from ice sheets in Antarctica. Based on the data shown in the graph, which of the following is the most plausible hypothesis for the cause of the trend in CO2 levels from about 5,000 years ago to the present?
Human activity, especially the burning of fossil fuels, has led to an increase in anthropogenic carbon dioxide emissions. This has caused a doubling in the concentration of CO2 in the atmosphere.
HCFCs were originally introduced as a solution to help phase out the use of CFCs. Which of the following most likely contributed to the increased levels of HCFCs in the stratosphere over the past 30 year
Leaking of refrigeration and air-conditioning units
Major sources include synthetic fertilizers and car emissions
N2O
Sea Level Risks US East Coast
Ocean warming not only cause displacement of coastal populations due to flooding but they also impact marine species via: - Habitat loss - Metabolic changes - Reproductive changes Metabolic: disruption of trophic structures due to reduction of biodiversity
The graph above shows CO2 measurements taken from Mauna Loa, Hawaii, and the Vostok ice core, which was drilled from ice sheets in Antarctica. Which of the following hypotheses is best supported by the graph?
Temperatures were warmer 125,000 years ago than the average temperature over the past 400,000 years.
Which of the following best describes how the American crocodile has become endangered in the state of Florida?
The increasing use of coastal areas by human has destroyed much of the habitat of the species.
Based on the information in the map, which of the following is a likely consequence for the human population if the sea level continues to change in the same pattern?
There will be in an increase in the number of individuals who live in flood prone regions, and there will be an increase in the number of properties at risk of flooding.
The release of CFCs was banned under an international treaty written in which of the following cities? a.) Montreal b.) New York c.) Paris d.) Kyoto
a.) Montreal
One important drawback of the use of HCFCs as a replacement for CFCs is that HCFCs
are greenhouse gases that contribute to climate change
Which of the following is NOT a source of methane? a.) cows b.) aerosols c.) rice paddies d.) dead plants
b.) aerosols
Global warming is least likely to directly cause which of the following? a.) shifting grain belts towards the poles b.) falling sea levels in the Southern Hemisphere c.) coastal flooding and submersion of low-lying areas d.) an increase in the amount of water vapor in the atmosphere
b.) falling sea levels in the Southern Hemisphere
Marine biologists have found that increasing atmospheric carbon dioxide levels are lowering ocean pH, a condition known as ocean acidification. This also causes a decrease in the concentration of calcium carbonate ions. If this rise were to continue it would have a devastating impact on coral ecosystems because: a.) it would increase the number of crustaceans that act as keystone species in the coral reef ecosystem b.) it would decrease the ability of the corals for form their exoskeleton c.) it would increase the amount of dissolved oxygen beyond the tolerance of the coral d.) it would increase the turbidity of the water beyond the coral's range of tolerance
b.) it would decrease the ability of the corals for form their exoskeleton
Which component of CFC's catalyzes the conversion of ozone into atmospheric oxygen? a.) Carbon b.) Fluorine c.) Chlorine d.) Hydrogen
c.) Chlorine
Samples of atmospheric gases from past eras can most easily be obtained from which of the following sources? a.) Methane trapped in oil reserves b.) Different types of sedimentary rock c.) Gases trapped in polar ice caps d.) Tree ring measurements
c.) Gases trapped in polar ice caps
Characteristic(s) of an organism that increase its risk of becoming endangered include which of the following? I. Narrow distribution II. Fixed migratory patterns III. Feed on low trophic levels a.) I only b.) II only c.) I and II only d.) II and III only
c.) I and II only
Which of the following best describes the term "endemic species"? a.) a species colonizing a far-flung new range b.) a species that benefits from its relationship with a second species c.) a species found in one specific region d.) a species that spreads disease
c.) a species found in one specific region
Which greenhouse gas spends the least amount of time in the upper troposphere? a.) carbon dioxide b.) methane c.) water vapor d.) CFCs
c.) water vapor
Which of the following is NOT true about stratospheric ozone? a.) Stratospheric ozone thinning increased after the creation and widespread use of CFC's. b.) Stratospheric ozone thinning contributes to an increase in skin cancer and cataracts in humans. c.) Stratospheric ozone naturally absorbs UV radiation via its formation and destruction. d.) Stratospheric ozone thins naturally in the Antarctic every April.
d.) Stratospheric ozone thins naturally in the Antarctic every April.
All of the following statements about invasive exotic species are true EXCEPT: a.) They may compete with native species for food. b.) They may prey on native species. c.) They are generally introduced by human activity. d.) They tend to have low reproductive rates.
d.) They tend to have low reproductive rates.
A health impact associated with increasing ozone loss is: a.) asthma b.) neurological disorders c.) chronic bronchitis d.) cataracts
d.) cataracts
Which of these is NOT a definitive cause of coral bleaching
decreased tourism
Positive Feedback Loop
enhance or amplify changes; this tends to move a system away from its equilibrium state and make it more unstable.
As the Earth warms up, snow on mountains melts, exposing the ground. the ground has a lower Albedo than the snow and absorbs more heat. this causes the Earth to warm up even more, melting more snow. this describes a what?
positive feedback loop
Based on the information in the map, which areas in the United States have experienced the greatest sea level rise?
the Northeast and the Gulf of Mexico
What affect to clouds have on average global temperatures?
they have both a warming and cooling effect
