APES Unit 9

Natural Greenhouse effect

This warms the earth’s lower troposphere and surface. Gases like CO2, H2O, and methane absorb infrared radiation from the atmosphere and re-emit it in every direction in the lower troposphere , helping to maintain a temperature suitable for life.

Natural cooling process

Large amounts of heat are absorbed when liquid surface water evaporates. The water vapor molecules rise and condense to form droplets in the clouds. Then, they release their stored heat in the troposphere.

infared

electromagnetic radiation with wavelenghts longer than visible light but shorter than microwaves

Major greenhouse gases

H2O, CO2, CH4, N2O, CFCs

water vapor

the earth’s most abundant greenhouse gas, responsible for half of the Earth’s greenhouse effect

CO2

Carbon dioxide; most crucial greenhouse gas, responsible for two-thirds of anthropogenic global warming and drives ocean acidification by dissolving into seawater and lowering its pH

CH4

methane; a hazardous air pollutant and contributes to the formation of ground-level ozone

N2O

nitrous oxide; a potent greenhouse gas, mainly produced from agricultural and industrial activities.

ozone

natural ozone in the stratopshere Acts as a protective barrier that prevents UV radiation from reaching the earth’s surface

ground-level ozone is bad because it can trigger health and environmental problems

Milankovitch Cycles / glacial periods

cyclical changes in Earth's orbit and axial tilt that affect climate patterns and contribute to the timing of ice ages.

air bubbles

when trapped in ice cores and ocean sediments, air bubbles can uncover information about past temperature trends, greenhouse gas concentrations, snowfall, forest fire frequency, etc

calcium carbonate foraminifera exoskeletons

used to determine age and temperature of marine sediments, providing insights into past ocean conditions and climate changes.

clouds

warming effect: clouds absorb and release heat into the troposphere

cooling effect: reflect sunlight back into space

Particulates

can increase cloud cover and can have a high albedo and reflect more incoming sunlight back into space, keeping days cooler. But, nights are warmer because hear cant be radiated back into space

albedo

the ability of a surface to reflect sunlight

effects of climate change

increased air pollution-related deaths, melting permafrost, rising sea levels, agricultural shifts, ocean warming, coral bleaching, increase spread of tropical disease

melting permafrost

as permafrost thaws, methane is released into the atmosphere, which absorbs heat and warms the tundra more, leading to more permafrost thawing

relationship between coral and zooxanthellae

Corals have a mutualistic relationship with zooxanthellae, a type of algae. The zooxanthellae provide nutrients to the coral, and the coral provide a habitat for the zooxanthellae. When the coral get stressed, they eject the zooxanthellae. While some corals are able to recover, many do not.

stress linked to coral bleaching events

abnormal water temps, nutrient pollution from runofff, overfishing, toursim, change ins salinity, dredging turbidity

ocean acidification

when the ocean declines in pH due to an increase in carbon dioxide diffusion in the water

Coral reefs

home to more than 25% of all marine life

protect shoreline from storm surges and erosion

habitat for fish

provide source for ecotourism money

potential sources of medicine

ocean and wind currents

gulf streams play a large part in regulating surface temperatures

wind currents transport heat throughout the earth

how to reduce threat of global warming

• reduce fossil fuel use

• shift to carbon free

• plant more trees

• soil sequestration

• inject CO2 into deep ocean

• pump CO2 into unmineable coal

Kyoto protocol

• require 39 developed countries to cut missions of CO2, CH4, and N2O

• does not require poor developing countries to make any cuts

• US withdrew participation in 2001

The Paris Agreement

• legally binding international treaty on climate change

• Its overarching goal is to hold “the increase in the global average temperature to well below 2°C above pre-industrial levels” and pursue efforts “to limit the temperature increase to 1.5°C above pre-industrial levels.”

Ozone Depletion in the Stratosphere

The gradual thinning of the ozone layer in the stratosphere caused by the release of chemicals such as chlorofluorocarbons (CFCs). This depletion allows more ultraviolet radiation to reach the Earth's surface, leading to harmful effects on human health and the environment.

CFC

• 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 CFC’s 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.

Montreal Protocol

phase out of substances responsible for ozone depletion, starting in 1989

98% of ozone depleting substances phased out within 25 years

Harmful effects of UV radiation

skin cancer, cataracts and sun burning, suppression of immune systems, impact on crops and animals, reduction of ocean phytoplankton, degradation of paints and plastic material