unit 9 (global change)

stratospheric ozone

a thin layer of ozone formed in the stratosphere; blocks UV-B and UV-C radiation, protecting life on Earth from the harmful radiation and allowing for life to continue to survive

causes of stratospheric ozone depletion

chlorofluorocarbons (CFCs) are an anthropogenic cause and the melting of ice crystals in the atmosphere during Antarctic spring is a natural cause

chlorofluorocarbons (CFCs)

refrigerant chemicals and propellants in aerosol containers that release free chlorine atoms after experiencing UV radiation; the free chlorine atom will bond to an oxygen atom in ozone (O₃) and convert it to O₂

the free chlorine atom can affect multiple ozone molecules, not just one

antarctic spring

causes an ice crystal melt in the atmosphere, which consequently leads to the formation of polar stratospheric clouds; these clouds, in the presence of chlorine nitrate and hydrochloric acid, give off free chlorine atoms

reducing ozone depletion

replacing CFCs with hydrofluorocarbons (HFCs), which are still greenhouse gasses, but don’t break down ozone at all

principal greenhouse gasses

carbon dioxide (CO₂); methane (CH₄); water vapor; nitrous oxide (N₂O); and CFCs

greenhouse effect

supports life on Earth by providing for the temperature on Earth that life requires to survive

however, if the amount of greenhouse gasses increases drastically, then it is possible for the climate of Earth to change/warm by too high of a degree

water vapor

has a very short residence time in the atmosphere, and thus, despite being a greenhouse gas, doesn’t contribute heavily to climate change

temperature controls the quantity of water vapor that the atmosphere can hold (higher temperatures lead to higher quantities of water vapor)

global warming potential (GWP)

a measure of how much a given molecule of gas can contribute to the warming of the atmosphere over a 100 year period, relative to CO₂

GWPs of various greenhouse gasses

CO₂ has a GWP of 1

From highest to lowest GWP (all greater than 1): CFCs, nitrous oxide, methane

causes of rising sea levels

increased global climate results in thermal expansion and the melting of polar and glacial ice, both of which are caused by increasing greenhouse gasses in the atmosphere

thermal expansion

the phenomenon where water molecules move slightly further apart when heating, and thus can cause sea levels to rise if large quantities of water molecules move slightly apart

effects of rising sea levels

• a decrease in biodiversity in arctic and tundra ecosystems

  • relocation of coastal human populations inland

disease vectors

living organisms that can transmit diseases from human to human or animal to human

examples: mosquitoes, ticks, and fleas that carry, malaria, Zika, West Nile, dengue fever, cholera

disease vector migration

typically migrate as a result of global climate change, which is caused by increases greenhouse gasses, towards the poles; results in larger human populations at risk of catching diseases

historical climate change

carbon dioxide data and ice cores allowed for scientists to determine that the Earth' has undergone climate change throughout geologic time, leading to periods of warming and cooling for the planet

effects of climate change

rising temperatures; rising sea levels, which displaces coastal population; and the melting of permafrost, which furthers the rise of temperature due to the release of CO₂ and CH₄

effects of climate change on marine ecosystems

positive effects:

• newly created habitats on now-flooded coastal shelves can increase biodiversity in the area

negative effects:

• organisms that live in deeper portions of the photic zone may no longer receive the light necessary for survival

effects of climate change on atmospheric currents

widens and weakens the Hadley cell, because the temperature difference between the equator and poles deceases, leading to air ascending and expanding further from the equator before decreasing in temperature and sinking down to the Earth’s surface

• shifts subtropical zones (arid regions) towards the poles

weakens and destabilizes the jet stream, since it is driven by the temperature difference between the polar and subtropical regions, which is decreasing drastically

effects of climate change on ocean circulation

ice melt from greeland and other areas results in a buildup of cold freshwater in the North Atlantic,

ocean currents

also called the ocean conveyor belt; redistributes heat, from the equator, salt, and nutrients, by mixing ocean waters

polar amplification

a phenomenon where the polar regions of Earth are warming faster than other regions, because ice and snow are melting, allowing for more infrared radiation to be absorbed by the polar regions, leading to more ice and snow melting

effects of ice and snow loss on ecosystems

in polar ecosystems it correlates to habitat loss, as many organisms require ice cover in order to find food or live

causes of ocean warming

increased greenhouse gasses cause average temperatures to rise, leading to more infrared radiation being absorbed by the oceans, and consequently causing a rise in ocean temperatures

effects of ocean warming on marine species

mating seasons, or reproductive timings, altered as a result of temperature changes since they are tied to seasonal temperature; habitat loss

coral bleaching

as oceans warm algae leaves the ecosystem, since algae has a narrow ecological range of tolerance, and thus it causes the coral to lose its color and possibly die, since algae is a source of glucose for the coral

ocean acidification equation

CO₂ + H₂O —> H⁺ + HCO₃^-

ocean acidication

a phenomenon that results from the combination of carbon dioxide and the ocean’s water as a result of the direct exchange between the atmosphere and the ocean

calcification

the process by which marine organisms use calcium and carbonate ions to build a calcium carbonate shell

ocean acidification’s effect on calcification

forms a bicarbonate ion that limits the amount of carbonate ions that are available for organisms, including coral, to build shells

anthropogenic causes of ocean acidification

fossil fuel combustion, deforestation, and coal/gas combustion; primarily driven by causes that release carbon dioxide, although acid precipitation can also decrease the pH of oceans

invasive species

a species not native to an area; often a cause of human transportation; the species is able to thrive because of a lack of natural predator; can be highly competitive for resources; highly adaptable

typically r-selected and/or generalists

zebra mussel

introduced into the United States via a ship; aggressive filter feeders, and thus eat algae that are required by other organisms

kudzu vine

planted to limit soil erosion in the Southern United States; grows extremely rapidly, outcompeting native plants for sunlight; no predator-control of the organisms

asian carp

brought in to control algae growth in aquatic farms; outcompeted native fish for food and space in the Mississippi River; decreases fishery production and value

controlling invasive species

laws that prevent the transportation of invasive species' and their common hosts; cleaning and inspecting boats for invasive species; introducing a natural predator; and physically removing invasive species

causes of species endangerment

extensive hunting; specific species require special food and habitat needs, so changing climates could push certain habitats out of their range of tolerance; and the possibility of native species being outcompeted by invasive species

protection of species

the criminalization of poaching; the protection of wildlife habitats, including the creation of wildlife preserves and national parks; and the passing of legislation to protect species

HIPPCO

the leading causes for a loss in biodiversity: habitat fragmentation or loss, invasive species, population growth, pollutants, climate change, and over-exploitation

habitat fragmentation

the result of large habitats being broken down into smaller, isolated areas; caused by the construction of roads and pipelines, the clearing of land for agricultural or urban land use, and logging

habitat corridors

a solution to habitat fragmentation that involves the connection of fragmented areas with slices of land that replicate the habitat that was fragmented

domestication

the use of plants and animals, typically, for economic services and financial gain; generally decreases genetic and species biodiversity