Module #64

Consequences of Global Climate Change

Module Introduction:

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• A wide range of environmental indicators demonstrate that global warming is affecting global processes and contributing to overall global change.
• In many cases, we have clear evidence of how global warming is having an effect.
• In other cases, we can use climate models to make predictions about future changes.
• As with all predictions of the future, there is a fair degree of uncertainty regarding the future effects of global warming.
• In this module, we will discuss how global warming is expected to affect the environment and organisms living on Earth.

Module 64: Consequences of Global Climate Change

Essential Knowledge

8.15 Pathogens and Infectious Disease (Modules 56, 64)

• Pathogens adapt to take advantage of new opportunities to infect and spread through human populations.
• Specific pathogens can occur in many environments regardless of the appearance of sanitary conditions.
• As equatorial-type climate zones spread north and south in to what are currently subtropical and temperate climate zones, pathogens, infectious diseases, and any associated vectors are spreading into these areas where the disease has not previously been known to occur.
• Poverty-stricken, low-income areas often lack sanitary waste disposal and have contaminated drinking water supplies, leading to havens and opportunities for the spread of infectious diseases.
• Plague is a disease carried by organisms infected with the plague bacteria. It is transferred to humans via the bite of an infected organism or through contact with contaminated fluids or tissues.

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Essential Knowledge

8.15 Pathogens and Infectious Disease (Continued)

• Tuberculosis is a bacterial infection that typically attacks the lungs. It is spread by breathing in the bacteria from the bodily fluids of an infected person.
• Malaria is a parasitic disease caused by bites from infected mosquitoes. It is most often found in sub-Saharan Africa.
• West Nile virus is transmitted to humans via bites from infected mosquitoes.
• Severe acute respiratory syndrome (SARS) is a form of pneumonia. It is transferred by inhaling or touching infected fluids.
• Middle East Respiratory Syndrome (MERS) is a viral respiratory illness that is transferred from animals to humans.
• Zika is a virus caused by bites from infected mosquitoes. It can be transmitted through sexual contact.
• Cholera is a bacterial disease that is contracted from infected water.

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Essential Knowledge

9.5 Global Climate Change (Modules 62-64)

• The Earth has undergone climate change throughout geologic time, with major shifts in global temperatures causing periods of warming and cooling as recorded with CO₂ data and ice cores.
• Effects of climate change include rising temperatures, melting permafrost and sea ice, rising sea levels, and displacement of coastal populations.
• Marine ecosystems are affected by changes in sea level, some positively, such as in newly created habitats on now-flooded continental shelves, and some negatively, such as deeper communities that may no longer be in the photic zone of seawater.
• Winds generated by atmospheric circulation help transport heat throughout the Earth. Climate change may change circulation patterns, as temperature changes may impact Hadley cells and the jet stream.
• Oceanic currents, or the ocean conveyor belt, carry heat throughout the world. When these currents change, it can have a big impact on global climate, especially in coastal regions.

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Essential Knowledge

9.5 Global Climate Change (Continued)

• Climate change can affect soil through changes in temperature and rainfall, which can impact soil’s viability and potentially increase erosion.
• Earth’s polar regions are showing faster response times to global climate change because ice and snow in these regions reflect the most energy back out to space, leading to a positive feedback loop.
• As the Earth warms, this ice and snow melts, meaning less solar energy is radiated back into space and instead is absorbed by the Earth’s surface. This in turn causes more warming of the polar regions.
• Global climate change response time in the Arctic is due to positive feedback loops involving melting sea ice and thawing tundra, and the subsequent release of greenhouse gases like methane.
• One consequence of the loss of ice and snow in polar regions is the effect on species that depend on the ice for habitat and food.

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Essential Knowledge

9.6 Ocean Warming (Module 64)

• Ocean warming is caused by the increase in greenhouse gases in the atmosphere.
• Ocean warming can affect marine species in a variety of ways, including loss of habitat, and metabolic and reproductive changes.
• Ocean warming is causing coral bleaching, which occurs when the loss of algae within corals cause the corals to bleach white. Some corals recover and some die.

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Impacts of Global Climate Change

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• Melting of permafrost, polar ice caps and many glaciers around the world.
• Rising sea levels due to the melting of glaciers and ice sheets and thermal expansion (as water warms it expands).
• Ocean Acidification and Coral Bleaching
• The impacts of climate change on vegetation are complicated:
• Plant cover will initially expand as the Arctic warms. This lowers global albedo as plants absorb more sunlight and generate more warming than ice/snow.
• Excessive global warming is expected to produce a net increase in plant growth cover but ultimately undermine biodiversity and ecosystem services.
• Global warming → heat waves → heat sickness, violence and civil unrest
• Change in precipitation patterns and increases in storm intensity

How will the impacts of climate change listed here influence ecosystem services? How does this jeopardize our long-term sustainability?

Predicted Impacts of Climate Change

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• These maps were taken from the book, “On the Move” by Abrahm Lustgarten.
• They illustrated the systemic impacts climate change is expected to have on human society based on the latest modeling.
• While you would not be expected to memorize these maps, you should be able to read and interpret them to get a better understanding of the impacts of climate change in the future.

Predicted Impacts of Climate Change

The Effects of Climate Change on the Northern Ice Cap

• Because northern latitudes have experienced the greatest amount of global warming, the extent of the ice cap near the North Pole has been declining over the past 3 decades.
• The polar ice cap reaches its minimum late in the summer of each year, so we can look for a trend by examining the extent of ice each September.
• From 1979 to 2013, the polar ice declined an average of 14 percent per decade.

Potential Benefits of Melting Ice Caps

• If the Arctic continues to experience increasing temperatures, openings in sea ice will continue to expand and the Arctic ecosystem will be negatively affected.
• However, this may also result in some benefits for people:
• New shipping lanes could reduce travel distance for commerce.
• It is estimated that 25% of all undiscovered oil and natural gas lies below the polar ice cap, expanding our global supply of fossil fuels*.

*(Of course this would contribute to a positive feedback loop that accelerates global warming).

The Effects of Climate Change on Antarctica and Greenland

• Measurements of ice mass from 2002 to 2013 have detected decline in both (a) Antarctica and (b) Greenland.
• As ice sheets, ice caps and glaciers melt, albedo decreases, resulting in less solar energy being reflected back into space and more being absorbed, contributing to warming.

Permafrost

• Permafrost refers to permanently frozen ground that exists in high altitudes and high latitudes including the tundra and boreal forests.
• About 20% of land on Earth contains permafrost which in some places can be 1,600 meters (1 mile) thick.

• Melting permafrost poses numerous challenges:
• Overlying lakes can reduce in size as lake water drains deeper into the ground.
• Structures including homes and pipelines can experience physical damage as the ground subsides.
• Previously frozen stores of organic matter can begin to decompose, adding more carbon (e.g. carbon dioxide and methane) into the atmosphere contributing to an amplifying feedback loop.

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Global Climate Change is Already Affecting Organisms�

• Wild plants and animals can be affected; the growing season for plants has changed and animals have the potential to be harmed if they can’t move to more appropriate climates.
• Humans may have to relocate resulting in climate refugees, civil unrest and economic consequences.
• Some diseases like those carried by mosquitoes could increase in prevalence as conditions become more favorable for growth.
• Corals are particularly sensitive to global warming because their range of temperature tolerance is quite small.

Sea Level Rise

• Sea Level Rise: The increase of ocean surface levels due to melting ice and thermal expansion related to global warming. Since at least the start of the 20th century, the average global sea level has been rising.
• Between 1900 and 2016, the sea level rose by 16–21 cm. 
• Satellite radar measurements reveal an accelerating rise of 7.5 cm from 1993 to 2017, which is a trend of roughly 30 cm per century.
• Albedo will also play a role: As sea level rises, land areas become replaced with comparatively darker ocean water → more solar energy being absorbed → global warming.

Thermal expansion: the tendency of substances (e.g. water) to increase in volume when heated. As temperatures rise, the oceans will take up comparatively greater volume.

NOAA: Sea Level Rise Viewer

This web tools allows you to view sea level rise and potential coastal flooding impact areas and relative depth.

Ocean Acidification

• Ocean Acidification: The ongoing decrease in the pH of the Earth's oceans, caused by the uptake of carbon dioxide from the atmosphere. 
• When CO₂ from the atmosphere dissolves into the oceans, it reacts with H₂O to form H₂CO₃ (carbonic acid).
• Carbonic acid releases H⁺ ions, thereby reducing the pH of the oceans → ocean acidification.
• This has multiple, long-term, severe impacts marine life.

NOAA

Ocean Acidification

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Impacts of Ocean Acidification

• Marine organisms combine calcium and carbonate ions to form calcium carbonate to build sea shells.
• However, as the oceans become more acidic, the carbonate ion becomes more rare, making it more difficult for sea shell forming organisms such as corals and mollusks to form shells. This is especially dangerous as the ocean water becomes more corrosive as it acidifies.
• Coral reefs are one of the most productive habitats on earth and sport immensely high biodiversity. The loss of coral reefs undermines global marine biodiversity and ecosystem services.

Coral Bleaching

• Corals form a mutually beneficial relationship with algae; exchanging protection for sugars.
• The algae living with the corals cannot tolerate environmental change such as changes in temperature or pH caused by excess carbon dioxide emissions.
• When the algae become stressed, they eject from the coral, turning the coral white and ultimately killing the coral. 
• Coral bleaching is also caused by pollution, which is increasing.

Coral Bleaching: A phenomenon that occurs when coral polyps expel algae that live inside their tissues. 

Climate change is threatening coral reef ecosystems. 27% of the world’s coral reefs have already been lost with 60% losses predicted in the next 30 years.

Climate Change Will Impact Human Society

• Incidence of heat exhaustion and heat sickness will increase, resulting in increased aggression, violence and crime.
• Predicted reductions of crop yields and available food supply.
• Predicted reduction and reversal of economic growth. In 2020, the world Economic Forum ranked climate change as the biggest risk to the economy and society.
• Sea level rise will inundate some areas like Miami or New Orleans and completely submerge others like the Maldives.
• Increased political and social destabilization leads to civil unrest, conflict and refugee migration which propagates further unrest, conflict and migration.

Assessing Uncertainty�

Combating Climate Change

Responding to climate change will require multiple strategies:

• Adaptation: (minimize the damage) anticipating the adverse effects of climate change and taking appropriate action to prevent or minimize the damage they can cause, or taking advantage of opportunities that may arise.
• Examples of adaptation measures include large-scale infrastructure changes, such as building defenses to protect against sea-level rise, as well as behavioral shifts, such as individuals reducing their food waste.
• Mitigation: (minimize the change) making the impacts of climate change less severe by preventing or reducing the emission of greenhouse gases (GHG) into the atmosphere.
• International agreements and legislation like the Kyoto Protocol.
• Emerging technologies can help reduce atmospheric carbon dioxide levels.

According to a recent study from the University of Southern California and the United Nations Foundation many of the words and phrases that scientists use to talk about climate change are not understood by the general public.

Combating Sea Level Rise

• A living shoreline is a protected, stabilized coastal edge made of natural materials such as plants, sand, or rock. Unlike a concrete seawall or other hard structure, which impede the growth of plants and animals, living shorelines grow over time.
• Living shorelines are generally cheaper than concrete alternatives and have the benefit of providing biodiversity and ecosystem services like erosion control.
• In areas where cones of depression are generating subsidence, groundwater recharge can reverse the process and limit the impacts of sea level rise.

Living Sea Shores are an example of ADAPTATION

Vulnerability to Sea Level Rise and Flooding

• Flooding will become increasingly prevalent as sea levels rise.
• Areas at or below sea level like Miami or New Orleans are the most vulnerable to flooding.
• Levees and industrial water pumps can offer protection but are static, expensive defenses and can also fail as they did during Hurricane Katrina.
• How can we provide more sustainable solutions like with “amphibious architecture” that can float out of harm’s way in the figure to the right?

Levees, water pumps and amphibious architecture are examples of ADAPTATION

APES Exam Environmental Legislation: Kyoto Protocol (1997)

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• Kyoto Protocol: An international agreement that sets a goal for global emissions of greenhouse gases from all industrialized countries to be reduced by 5.2 percent below their 1990 levels by 2012.
• Although the United States signed the original Kyoto Protocol, the U.S. Congress never ratified the agreement and the protocol has never been legally binding on the United States.
• In 2005 mayors from 141 U.S. cities and both major political parties gathered in San Francisco to organize their own efforts to reduce the causes and consequences of global warming.
• It was widely hailed as the most significant environmental treaty ever negotiated, though some critics questioned its effectiveness.

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The Kyoto Protocol is an example of MITIGATION.

Using Soil as a Carbon Sink

• Soil carbon storage is a vital regulating service, resulting from interactions of ecological processes.
• Human activities (such as desertification) affecting these processes can lead to carbon loss or improved storage.
• Total carbon in terrestrial ecosystems is approximately 3170 gigatons, 80% of which is found in soil.
• Repairing deteriorated soils would improve not only improve soil quality and food production but also improve global carbon sinks, helping to mitigate climate change.

Carbon capture in soil is an example of MITIGATION.

Carbon Removal Technolo-TREEs

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• Researchers, such as those at Climeworks, are looking at cost-effective ways of capturing CO₂ from the air, from coal-burning power stations, and from other emission sources.
• This captured CO₂ would be compressed and pumped into abandoned oil wells or the deep ocean, effectively removing carbon from the atmosphere and into the geosphere.

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• Carbon removal: An approach to stabilizing greenhouse gases by removing CO₂ from the atmosphere (also known as carbon capture or carbon sequestration).
• As plants (e.g. trees), perform photosynthesis, they sequester carbon in their biomass thereby helping to regulate climate (regulating service). Soil can also act as a massive carbon sink.

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Carbon Removal is an example of MITIGATION.

Engineering Responses to Climate Change

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In addition to carbon sequestration, there are additional strategies to responding to climate change:

• Using CRISPR to genetically modify organisms to make them more resilient to global changes (e.g. corals and crop species), enhance their ecosystem services (e.g. faster growing trees) or combat invasive species with ‘suppression drives’ that spread deleterious traits that can wipe out entire populations.
• Geoengineering to artificially control climate through the dispersal of aerosols in the stratosphere (e.g. sulfuric acid or calcium carbonate) to reflect incoming sunlight and cool temperatures much like volcanic eruptions do.

Genetic engineering and geoengineering are examples of ADAPTATION

The actual mechanisms of genetic engineering are probably beyond the scope of the AP exam, but still relevant and interesting.

Downsides to Technology

These approaches can have significant, even catastrophic, unintended consequences (negative externalities).

• GMOs and gene drives are powerful technologies we may not be able to control once unleashed in the biosphere.
• Geoengineering has similar risks for the physical environment. For example, we could imitate volcanoes and emit sulfate aerosols into the atmosphere. Sulfates have a high albedo and could reduce the solar energy reaching the Earth, but also generate acid deposition and harmful human health effects.
• Alan Robock: 20 Reasons Why Geoengineering May be a Bad Idea

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Case Study: Everglades

• Water diversion projects for irrigation, drinking water and other uses as well as alteration of runoff patterns by impermeable surfaces have significantly reduced the Everglades.
• Human land use changes converted wetland habitat → agriculture.
• As a result, the everglades are more prone to eutrophication and harmful algal blooms because of runoff from fertilizers and animal waste.
• Climate change will alter rainfall patterns, temperature, dissolved oxygen and habitat through changes in water quality/quantity, species distribution and sea level rise.

Sea-level rise and inundation scenarios for national parks in South Florida - NPS

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I would focus on knowing this as an example of the impacts of climate change and how to deal with them, rather than knowing all of the specific details.

Comprehensive Everglades Restoration Plan (CERP)

• The CERP was authorized by Congress in 2000 as a plan to "restore, preserve, and protect the south Florida ecosystem while providing for other water-related needs of the region, including water supply and flood protection."
• At a cost of more than $10.5 billion and with a 35+ year timeline, this is the largest hydrologic restoration project ever undertaken in the United States.

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I would focus on knowing this as an example of the impacts of climate change and how to deal with them, rather than knowing all of the specific details.

Module Review:

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• In this module, we learned that the warming of Earth due to human activities has had a number of effects.
• In regard to the environment, global warming has caused declines in the polar ice cap, declines in the ice masses of Greenland and Antarctica, melting of glaciers, thawing of permafrost, and increases in sea level.
• In regard to organisms, global warming has caused changes in the dates of flowering, bird migrations, insect emergence, and the length of the growing season.
• Scientists predict a number of additional effects with various levels of certainty, including more extreme temperatures, changes in global patterns of precipitation, more intense storms, and altered ocean currents.
• These predicted changes could affect many aspects of human life including where humans can live as well as their health.