ESS unit 6

Atmosphere layers

Feedback loops and systems

Atmosphere

the mixture of solids, liquids and gases that are held to the Earth’s gravitational force and are redistributed across the Earth through physical processes such as wind

Pressure gradient force

air moving from areas of high pressure to low pressure

Troposphere

the lower 16-17 km area of the atmosphere where most weather occurs.

Insolation

incoming solar radiation

Fundamental factor causing atmospheric circulation

unequal heating with latitude. Between 38S and 38N there’s excess energy, whereas polewards there is energy deficit meaning energy is transferred from low latitude to high to balance unequal heating

Distribution of energy in atmosphere to ground level

air moves towards the center of low pressures (convergence), rises, and spreads out when it reaches tropopause (divergence). When air converges at high altitude, it sinks and forms high pressure at ground level and diverges at ground level

Different greenhouse gases in the atmosphere

water vapour, CO2, tropospheric O3, Methane, nitrous oxide.

Greenhouse gases effects (GHGs)

permit incoming short-wave radiation from the Sun to pass through but can absorb long-wave radiation since incoming solar radiation and outgoing long-wave radiation operate at different wavelengths. Can also lead to warming or cooling effects depending on the amount of aerosol.

Black carbon (aersol)

fine particulate matter formed from the incomplete combustion of fossil fuels (40%), biofuels (20%), and biomass (40%). Only stays in atmosphere for days or weeks before removed by rain or snow

Impacts of black carbon

Direct: absorbs sunlight and reduces albedo,

Indirect: absorbs insolation and affects cloud cover,

snow and ice albedo: when deposited, reduces albedo and causes positive feedback loop causing increased surface temp and decreased ice cover,

indirect: changes in absorption or reflection of solar radiation through cloud cover changes

Greenhouse effect

natural process by which GHG and aerosol in the atmosphere absorb and re-emit long-wave infrared radiation that has been reflected from Earth’s surface back to Earth, warming the atmosphere

Enhanced Greenhouse effect

the increase in GHGs due to human activity

Climate

state of the atmosphere over a period of 30 years or longer, includes variables such as temperature, rainfall, winds, humidity, cloud cover and pressure

Impacts of climate change

changes in water availability, distribution of biomes and crop-growing areas, loss of biodiversity and ecosystem services, coastal flooding and sea level rise, ocean acidification, damage to human health

Biome shifting

climate change causing biomes to move with changes in global temperature. Ex: Plesticocene glaciations was covered in ice 18,000 years ago, and since then tundra climates shifted north and with time and increases in climate change are likely to continue shifting north

Coral bleaching

an effect of climate change, when the symbiotic algae that they support are lost, if prolonged the coral may die

Desertification

an effect of climate change, the spread of desert-like conditions due to human impacts and ecosystem changes

Ocean circulation

an effect of climate change, 2 main types are surface and vertical currents. Increases in global temperature cause changes in ocean and atmospheric circulation that affect regional climates and ecosystems

Sea level rise

an effect of climate change, caused by human activities such as ice sheets melting or tectonic plates depressing into the ground or being uplifted.

Climate change and plant productivity

Rising CO2 does improve productivity (carbon fertilization), however due to climate change, increased temperature, nutrient and water availability limit productivity. Higher temperatures accelerate plant life meaning less photosynthesis, and differences in temperature can breed pests, or make crops vulnerable, reducing the availability of crops.

Climate change impacts on societies

water supply disruptions, Agricultural disruptions, worsened labor productivity, natural resource changes, weakened human health, changes in infrastructure, tourism

Carbon sinks

anything that accumulates and stores carbon compounds, thereby removing CO2 from the atmosphere

Global action for climate change

Climate conferences such as the Paris climate conference in 2015 to agree a legal limit of global temperature rise to be 2C.

UNFCCC

foundation used to negotiate global agreements for reducing greenhouse gases and limiting the impact of global climate change. 198 countries in it, and meets every year to aim for net zero emissions.

Kyoto Protocol

a legal treaty that called for developed nations to cut GHG emissions by 5.2%. The USA withdrew despite emitting about 25% of the worlds CO2

Decarbonization

reducing or ending the use of energy sources that result in CO2 or GHG emissions and replacing them with renewable energy sources.

Carbon neutrality

when CO2 emissions are balanced by CO2 absorbed by carbon sinks

Mitigation strategies

reducing the process of global warming (geoengineering), reducing production of GHG (renewable energy, food choices, etc.) , and removing CO2 from the atmosphere (carbon sinks, sequestration, etc.)

Afforestation and rewilding

important way for taking CO2 out, increasing the area of land covered by trees

Adaptation strategies

2 main types,

Structural: flood defenses, desalination plants, and moving infrastructure.

Non-structural: drought resistant crops, vaccinations, land zoning, building code changes