Exam 2 global climate change

how does climate change affect ecosystems?

Some ecosystems might adapt to the change caused by climate change, but for others, the amount is too great. Leading to: Ecosystem destruction Loss of biodiversity Human activity is already pushing ecosystem resilience, and may lead to species extinction if they cannot adopt or migrate fast enough

Under climate change, why are coastal and low-lying regions (e.g., Bangladesh, southern Florida, New Orleans, Netherlands) at particular risk?

Southern Florida will be submerged with 4-8m (guaranteed by melting of Greenland) NYC and Boston would submerge with 6m rise

Warming is Associated with _____ of the Hydrological Cycle, and this Includes ______ in Precipitation Intensity and ______ in Dry Spell Length for Ma ?

Strengthening / Increases / Increases

Earth's orbital configuration? (Slide 22)

Summer sunlight at high northern latitudes was reduced Winter snow could survive summer Additional ice accumulated

What is the best estimate of climate sensitivity ?

3 degree celsius

How is this related to tipping points?

A threshold that subjects the climate to change

Does IPCC overstate the effects of climate change? (Slide 37)

No, it is actually understating the effects

An Initial Change Causes the Climate to Cool. According to the Chemical Weathering Thermostat...

Precipitation will decrease, decreasing weathering and decreasing CO2 removal.

Why are future projections of climate change uncertain?

Projections of climate change are uncertain because of we have access to a short climate record. Nonetheless, we can draw certain conclusions based on fossil fuel burning and climate models

Under RCP2.6?

Most conservative scenario: 1.2-2.8C (pre-industrial time)

Has this accelerated or dampened climate change?

Nature has somewhat reduced the human impact on atmospheric composition and climate

Is it a positive or negative feedback? (Slide 64)

Negative. Increased weathering (during warming) -> increased removal of CO2 -> reduction of initial warming

Are future projections of ENSO certain?

No b/c models don't agree on the basic question of whether the climate will become more or less compared to response to human impacts on climate change

What is meant by "abrupt(sudden) climate change"?

Occurs when the climate system is forced to transition to a new climate state at a rate that is determined by the climate system energy balance, and which is more rapid than the rate of change of external forcing.

As climate has changed in the geologic past, ecosystems (plants, animals, microscopic organisms, etc.) have shifted in response. How is past climate change different than projected future changes?

Past climate changes were slower than projected future changes How is this related to migration rates? Animals were able to adapt or move but now the rate of change exceeds migration speed What does this imply for ecosystems, biodiversity and individual species? Under 4K warming, what percentage of plant and animal species will be at risk of extinction? 40-70%

What is permafrost?

Permanently frozen soil (contains methane in it, when it melts it releases the CH4) How is it expected to change in a warmer world? It's slowly disappearing (Melting).. Releasing more CH4 What are some of the impacts of permafrost melting? Bridge Collapse Pipeline Breakage Roadway Degradation Contamination of Surrounding Environments

Are they effective at reducing fish and coral loss?

yes

With 6 meters of sea level rise, is New York City at risk of flooding?

yes

RCP2.6?

Future reduction of fossil fuel use

Ocean acidification effects of CO2?

no

why?

Water becomes less dense (expands) as it warms Melting of Ice

is population growth important

yes

How has CO2 varied over geologic time scales?

-500 MYA (mil. Years ago) CO2 levels were high, then fell, reaching a minimum 300 MYA at the height if the Permo-Carboniferous glaciations on Gondwana. -After that, levels rose and fell, reaching another maximum 175 MYA in the late Triassic. -They stayed relatively high through the next 100 MY (age of the dinosaurs reptiles lived in the Arctic) -Since then, CO2 has fallen, reaching another minimum close to present day. -Combined with paleo-temperature data, proxy CO2 data provide a climate sensitivity of 2-5°C (4-9°F)

What is the "faux pause"?

-> A period in time where temperatures didn't increase as rapidly over the past decade as they did in the prior decades. ->This led to a false notion where they believed was a "pause" in global warming.

What is El Nino Southern Oscillation (ENSO)?

-> ENSO is a natural irregular oscillation of the climate system, involving inter-related changes in: -> SSTs, currents, and winds across the tropical Pacific.

Under Business-as-usual, Projected Global Warming by 2100 is?

0.2-1.8°C

What caused it?

-> Natural factors caused it -> Background Volcanic Activity -> Short - Term reduction in Solar output -> Series of La Niña events, all of which had led to temporary surface cooling not taken into account in most model simulations.

La Nina?

-> Pool of warm water positioned farther west than normal, Southeast trade winds stronger than usual, Strong upwelling of cold, deep water, and Sea surface cooler than normal in eastern Pacific.

Coastal and low-lying regions are particularly vulnerable to climate change

-> Rising Sea Level -> Increased Hurricane Destruction -> Increased Coastal Erosion -> Larger Wave Heights

Uncertainty in Future Warming is Due to?

-> Uncertainty in future emissions -> Uncertainty in climate sensitivity -> Uncertainty in future population -> Uncertainty in energy demand -> "B=C, A=D, A=E" ~ Professor

How does the tropical Pacific change during El Nino?

-> Warm water flows eastward accumulating off South America, Downwarding, Southeast trade winds reverse or weaken

Ocean Feedbacks include?

-> Warmer ocean -> absorbs less CO2 -> Ocean acidification -> reduces CaCO3 production -> absorbs more CO2 -> Ocean acidification -> reduces CaCO3 production -> weakens biological pump -> absorbs less CO2 -> Decreased mixing of nutrients -> slows biological productivity -> weakens biological pump -> absorbs less CO2

El Nino is Associated With?

-> Weakening/reversal of southeast trade winds -> Warmer water in central/east tropical Pacific -> Reduction in cold upwelling off coast of South America -> Drier conditions near Indonesia -> Wetter conditions in southern United States.

With Continued Warming, the Biological Pump Will _______, Leading to_____.

-> weaken/more warming----I think

What are the main reservoirs of carbon?

-Atmosphere -Ocean -Vegetation, soils, and detritus on land

How are floods and droughts projected to change?

-Greater drought tendency in many regions -More frequent and intense flooding in many regions

How is precipitation projected to change?

-Increased winter precipitation in polar and subpolar regions -Decreased summer precipitation in mid-latitude regions -Decreased precipitation in subtropics -Increased precipitation near equator

why?

-Projected poleward shift of jet streams -Poleward expansion of Hadley Cell -Warmer atmosphere

If not, what does this imply for regional climate change projections?

-They are hampered by how some global wind and ocean currents will change -More frequent El Nino would mean an increase in winter precipitation, offsetting trends of increased drought -Increase would also favor worsening drought

What is a hysteresis loop?

-Two stable states in which the environment operates on. If the environment begins warming/cooling, the two stable states may be surpassed by two thresholds: the temperature for catastrophic ice sheet melting and the temperature for ice sheet regrowth. -Path back to the original condition can be much different than the path that led the system to the altered state

The recent "Pause" in Global Warming is

-natural factors -a false notion -related to a series of la nina event

emission scenarios are based on?

-population growth -per capita energy -economic growth -technological advances

Phytoplankton?

-they transfer fossil-fuel carbon dioxide from the atmosphere into the ocean - Ocean acidification reduces the production of calcium carbonate by phytoplankton which increase their calcification which further reduces the ocean's ability to take up fossil fuel CO2, this is a negative feedback Take CO2 from the atmosphere, and die. As they decompose, IF they sink, this transfers the carbon to the bottom of the ocean.

What is the range of climate sensitivity, according to IPCC?

1.5-4.5 degree Celsius

Sea level?

120 meters (395 ft) lower than present day sea level

If CO2 doubles, Our Best Estimate of How Much Earth Will Eventually Warm is?

3' C

Do all of our CO2 emissions stay in the atmosphere?

55% of the CO2 we emit "disappears"

If CO2 Quadruples, Our Best Estimate of How Much Earth Will Eventually Warm is?

6'C

What are positive feedbacks associated with the carbon cycle?

A warmer land leads to increased growth and respiration of soil microorganisms (more CO2 byproduct)

What is climate sensitivity ?

Amount of warming that we expect to occur when there is a change in the factors that control climate.(increase GHGs) expresses in terms of how much surface warming will occur in response to a doubling of CO2 from pre-industrial levels(280ppm)

In addition to coral, what other organisms are at particular risk of extinction due to climate change?

Amphibians Polar bears

heat waves ?

Are likely to become: More intense More frequent Longer lasting Greatest increase is predicted to occur in: Western US North Africa Middle East Here, feedback loops associated with decreased soil moisture may intensify summer warmth

How is extreme weather projected to change?

As climate changes, it is likely that the frequency and intensity of extreme weather events will change -8i8k Extreme weather is projected to become more common and exaggerated

How were atmospheric concentrations of greenhouse gases (GHGs) different?

CO2: 50% less of what it is today Methane: Was about ⅕ of what it is today. NO2: Was about ⅔ of what it is today

what is an ecosystem?

Definition: An interdependent community, consisting of: Plants Animals microscopic organisms A complex physical environment (All of these elements listed above interact to form a complex whole)

negative feedbacks?

Plants increase their growth in response to elevated CO2 levels (CO2 fertilization)

biodiversity?

Climate change may lead to species extinction, which in turn would decrease biodiversity. Between 40 - 70% animals will be extinct exceeding 4.0 degree rise in temp.

How does climate change stress human societies?

Climate change puts stress on human societies. It will likely lead to: -Greater competition for natural resources -Threats to food supplies -Increased risk to human health -International conflict Coastal and low-lying regions are at particular risk, because they are exposed to temporary flooding and permanent inundation caused by rising sea-level Warming could lead to more atmospheric pollution by accelerating ozone production and promoting air stagnation

Where do estimates of climate sensitivity come from ?

Climate models : certain types of climate models are tuned to different climate sensitivities Climate models: they compare observations from "instrumental records" the past 160 years. Estimate the impact of both human and natural forces Different types of climate models for different climate sensitivities Scientist look at each individual climate model and analyze which ones are more accurate to the actual observed temperature changes. Estimate the climate sensitivity values.

According to the IPCC, what is the most vulnerable ecosystem? Why?

Coral reefs are among the most vulnerable ecosystems because they have little scope for adaptation ( ALSO AMONG THE MOST DIVERSE) Coral reefs provide food for millions of people, serve as a defense barrier against tropical cyclones and tsunamis, and serve as a source for tourism impact (11.5B annually) Coral decline is caused by natural stressors ( disease, predation) and human activities ( overfishing runoff, coral bleaching)

What are some of the uncertainties associated with IPCC projections of future sea level rise (e.g., crevices/moulins)?

Crevices/Moulins are cracks/fissures in ice sheets, which allow melting water to accumulate further into the ice sheet, allowing more to break off. >New problems such as these are not accounted for in models yet.

food supplies?

Crops will suffer because of drought especially in South California which has a huge agricultural community.

How is it expected to change under additional global warming?

Decrease nutrients at the surface, ocean acidification

All stabilization targets require sharp _____ in CO2 emission following the peak, with the lower stabilization targets requiring ___ peak emissions.

Decreases / Sooner

How might climate change affect environmental refugees? Why?

If they can't adapt fast enough, they will die out. Due to drought and unfavorable agricultural/farming

How will climate change affect disease (Malaria, dengue, West Nile Virus)

Disease will spread Why? Insects and rodents that carry diseases range more widely as the climate barriers are lifted How is this related to mosquitos and other vectors? Disease carrying mosquitoes are spreading i.e zika

If not, where does it go?

Dissolves in the ocean, and is incorporated in living biomass (photosynthesis)

why are they valuable ?

Ecosystems are valuable because they assist us with: -Provisions - (food, fiber, medicinal products, and cosmetic products) -Environmental regulation - (Climate and water regulation, water and air purification, carbon sequestration, protection from natural disasters, disease and pests) -Cultural benefits - (Appreciation of, and interaction with, the natural world; recreational activities)

Scientists Estimate Climate Sensitivity Over the Last Several Centuries by?

Estimating Solar Variations from sunspots -> Estimating GHGs from ice cores -> Estimating volcanic eruptions from ice cores -> Estimating Past temperature variations form tree rings/ice cores

What does this imply?

False claim that global warming has stopped but it was only masked by fleeting natural factors

With modest warming, how will food production change?

Food production is expected to INCREASE with modest warming (1-2 degrees C) Regions such as U.S, Europe, and Canada will benefit from it Tropical/Subtropical climates will experience warmer temperatures and less precipitation THE HOTTER IT GETS = Undermine food supplies=more famine Is this dependent on region? Yes With more warming (>3C), how will food production be affected? NEGATIVE impacts for crops in all agricultural regions.

What are fossil-fuel emission scenarios?

Fossil Fuel Scenarios are created in an attempt to learn more about an uncertain future, scientists create and evaluate a range of scenarios (4) for greenhouse gas emissions. This exercise helps them to determine the scope of consequences for a variety of possible future fossil fuel use scenarios (divided between business as usual scenarios and conservation/mitigation scenarios) . There are 4 different scenarios (a range of 21st century policies) each representing a group of emissions scenarios for the future called "Representative Concentration Pathways (RCPs)" that are based on their total "radiative forcing" by 2100. -Each RCP is created by integrated assessment models that accounts for climate affects, economic, land use, demographic, and energy considerations -Emission scenarios are based on population, energy demand, economic growth, and technological advances. -"business as usual scenarios" (8.5): assume ever increasing rates of fossil fuel use -"conservation/mitigation scenarios" assume some future reduction for use. 4 Scenarios: RCP 2.6, RCP 4.5, RCP 6.0, & RCP 8.5 (only required to know 2.6 & 8.5) -RCP 2.6: Requires strong efforts of mitigation to reduce greenhouses concentrations before 2100 -RCP 8.5 (aka business as usual scenario) allows the greenhouse gas concentrations before 2100 to rise beyond the year 2100. This scenario is the closest to what might be considered business as usual

ice sheets?

Ice sheets covered much of Canada, Northernmost U.S, Scandinavia, And Europe.

What does this imply for future climate change?

If positive feedbacks often dominate, this says that the warmer land leading to the increased growth/respiration of soil microorganisms will feed into itself. It will overlap the negative feedback

How are these related to ice sheets?

If the climate warms too much (past a threshold) ice sheets melting will become unstoppable

Food Production is Expected to ______ With Modest Warming (< 3`C), But _____ With More Warming.

Increase/ Decrease

Intense rainfall events and flooding?

Increases in the frequency of intense precipitation events and flooding More moisture in a warmer atmosphere

What is RCP8.5?

Increasing fossil fuel use Representative Concentration Pathways

While many regions are projected to become drier, scientists predict that even in these regions:

Individual rain/snow events will become more intense Longer dry spells will separate them

Under the Higher Emissions Scenarios, the Rate of Climate Change _______ the Natural Migration Capacities of Most Plants.

Is larger Than

Why is it important?

It allows more CO2 to be absorbed at the surface. If the pump isnt present, this can mean that less CO2 is absorbed and less carbon in the carbon cycle >can be considered a positive feedback

Why do we care about ENSO?

It influences weather patterns across the globe

What is meant by climate change "uncertainty"?

It is inevitable when we have access to a short climate record.

what is biological pump?

It is the part of the oceanic carbon cycle responsible for the cycling of organic matter formed mainly by phytoplankton during photosynthesis (soft-tissue pump), as well as the cycling of calcium carbonate (CaCO3) formed into shells

How was the Last Glacial Maximum (LGM) different than today?

It was colder than today by 3 - 8 degrees

Under RCP8.5, how much warming does IPCC project by 2100?

Least conservative scenario: 3.8-6.8C (pre-industrial time)

All stabilization targets require sharp reduction in C02 emissions following the peak

Low stabilization levels require C02 emission rates to fall below the current rates to fall below the current rate within a few decades

What are MPAs?

Marine Protected Areas They restrict human activity for a conservation purpose, typically to protect natural or cultural resources Conserve biodiversity

why?

More heat > more evaporation > more precipitation

How are they related to solar intensity?

More sunspots= brighter sun Less sunspots= dimmer sun

fresh water supplies

More than 15% of the world's population depends on the seasonal melt of high elevation snow/ice for fresh water The melting of glaciers and ice caps represent a serious threat

Another way to measure climate sensitivity is by studying the response to change natural factors previous centuries

Proxies date : ice cores Tree rings Sun spots Volcanic eruptions Aerosol deposits GHG concentrations Air bubbles Geologist estimated that there was as much as 1500ppm of CO2 in the past. So it is important to study the past in order to predict how much climate sensitivity works with a larger range of CO2 models only simulate the observed cooling during glacials when CO2 levels are low .

How well did past IPCC projections do? (Slide 35)

Quite well! model projections (due to natural factors), projected warming is consistent w/ observations oil

If not, then what needs to be done?`

Reduce or eliminate CO2 emissions Sequester CO2 before it goes into the atmosphere. (or corals will be unable to grow skeletons by the end of this century)

What do they require?

Require sharp reductions in CO2 emissions following the rate Emission rates fall below current rate within a few decades

Respiration?

Respiration is responsible for the transaction of carbon from the atmosphere to the biosphere

In the Carbon Cycle, What Process is Represented by the Red/Blue Arrow?

Respiration/Photosynthesis

How is sea level projected to change by 2100? (Slide 69)

Rise between 0.5-1.2 meters (1.6-3.9ft)

human health ?

SMOG is produced when emissions from incomplete fossil fuel combustion react to produce pollutants One such pollutant is tropospheric ozone, a lung irritant that also damages crops, buildings and forests. Warming accelerates ozone production & promotes air stagnation, leading to increased tropospheric ozone levels A 1 degree increase in warming and increase in air pollution also increases asthma and respiratory illnesses (Aggressive CO2 reduction (RCP2.6) could save hundreds of thousands of premature deaths by O3 pollution annually)

What is the climate significance of sunspots?

Sunspots have been measured since back when Galileo first was able to. The measurements demonstrate the temperature is rising since brighter light equals hotter regions. They relate to solar intensity because the more sunspots the more coronas, premises, and the more flares form. Once they form they radiate to earth and hit our atmosphere → intensity impact.

Is the surface warming spatially uniform?

Surface warming varies based on location. Some areas will radiate more than others.

For a lower stabilization target, what is required? The lower the CO2 stabilization target, the sooner peak emissions must occur:

The need to act now: Lower C02 stabilization levels can be achieved only with lower peak emissions: The 750 ppm target allows C02 emission rates to increase by 100%

What causes the delay in warming in response to a doubling of CO2

The ocean takes longer to warm (ocean warming )

What is the chemical weathering thermostat?

The process that turns rocks into soil and dissolved salts in rivers. Atmospheric CO2 dissolved in rain forms carbonic acid, increasing weathering process

What is the carbon cycle?

The series of processes by which carbon compounds are interconverted in the environment, typically between the land, ocean and atmosphere

IPCC Estimates of Future Sea Level Rise May Be...

Underestimated

hurricanes?

There has been a more recent trend toward more intense hurricanes in certain ocean basins (tropical atlantic) These trends closely mirror warning SSTs (sea surface temperatures) Warmer SSTs: All other things being equal- will fuel: More intense hurricanes, with stronger sustained winds Less Often but more intense, causing more damage

. How are soil microorganisms related to carbon cycle feedbacks? (Slide 59)

They decompose organic matter and fart out CO2

Which of the Following are True Regarding Marine Protected Areas?

They restrict human activity for a conservation purpose -> They protect natural or cultural resources.

What is meant by a CO2 stabilization target?

To prevent atmospheric C02 from exceeding 450 ppm, fossil fuel use must peak by 2020 Even with this: Global climate increases an additional 1 degree or 2 degrees since preindustrial times Sea level rises by at least 0.5 m by 2100

How does global warming affect air pollution? Why?

Warming accelerates ozone production and promotes air stagnation, leading to increased tropospheric ozone levels. For every 1% pollution increase, there will be 20,000 additional related pollution deaths

A conservation/mitigation scenario?

What the name says, we reduce or mitigate (same thing really) our fossil-fuel usage. (RCP2.6)

what is "coral bleaching"

When corals lose their symbiotic algae that gives them their color caused by hot ocean temperatures

How does sea level rise affect Gross Domestic Product (GDP)?

With only 1m of sea level rise, losses of land and GDP are sizeable COSTLY People would have to relocate

Is photosynthesis important?

Yes, photosynthesis is responsible for the transaction of carbon between the land biosphere and atmosphere

what are they based on ?

are based on their total "radiative forcing" by 2100. Radiative forcing: difference between insolation (sunlight) absorbed by the Earth and energy radiated back to space.

dry spells?

longer more intense

Can they protect coral from global warming?

no

Is it truly indicative of a pause in global warming?

no

Are the health impacts associated with climate change uniformly distributed across the globe?

no Who is more susceptible? The poor because they do not have access to resources, (but also children, elderly, and those in low lying coastal regions) Why? Inadequate access to AC, poor infrastructure, lack of health care, lack of emergency response facilities.

plants?

plants use CO2 to grow

Which type of feedback dominates?

positive

What is meant by a "business-as-usual" scenario? (Slide 26)

the burning of fossil fuels as it is right now

severe frost?

they are going to decline to due warming