ess topic 6

differential heating of the atmosphere creates

tricellular model — redistributes heat from the equator to the poles. This circulation disperses the heat across the planet, reducing the heat at the equator andincreasing the temperature in higher latitudes.

systems diagram to represent atmospheric system

GHGs and the greenhouse effect

GHGs: co2, water vapour, ch4, NOx

• the sun emits energy in the form of solar radiation which enters the Earth’s atmosphere.

• some thermal energy is reflected from Earth’s surface but most is absorbed and re-emitted back from the Earth’s surface

• some thermal energy is absorbed by GHGs which causes thermal energy to be re-emitted in all directions.

• reduces the thermal energy lost to space and traps it within the Earth

climate + main factors affecting it

it describes the typical conditions that result from physical processes in the atmosphere.

The main factors impacting climate in an area are seasonal variations in temperature and precipitation.

general impacts of climate change on exosystems

• affects the resilience of ecosystems

• leads to biome shifts

local impacts of climate change

coral bleaching

• cause: increased sea temp causes corals to expel algae, causing corals to lose their color and lose their main food source — leads to bleaching and coral death

• impact: loss of biodiversity as many marine species lose their habitat

• ex: great barrier reef

desertification

• cause: prolonged droughts and higher temperatures. unsustainable land practices like deforestation and overgrazing

• effects: loss of arable land and vegetation, leading to soil erosion → reduced agricultural productivity and displacement of communities

• ex: sahel region in africa

global impacts of climate change

changes to ocean circulation

• cause: melting ice caps and glaciers increase freshwater input into oceans, disrupts normal currents and circulation patterns

• effects: altered weather patterns, changes in marine and costal ecosystems, changes in fish migration and distribution which affects fisheries

• ex: colder winters in europe, and warmer arctic temps

sea-level rise

• cause: melting ice caps and glaciers, thermal expansion of seawater due to higher temperatures

• effects: coastal flooding and erosion, impacting ecosystems like magroves and salt marshes. loss of habitats for species.

• ex: maldives

regional impacts on natural productivity

increased productivity

• northern regions — warmer temp can extend growing season and increase vegetation → expansion of suitable areas for agriculture and forestry

decreased productivity

• tropical regions — higher temps and unpredictable rainfall can harm crops

factors affecting ecosystem resilience

biodiversity

• high biodiversity: increases resilience, ecosystems can adapt to changes

• low biodiversity: decreases resilience, ecosystems become more vulnerable

• impact of CC: can lead to habitat loss, altered food webs, weather events → reduce biodiversity

habitat fragmentation

• connected habitats: enable species to migrate and adapt to changes

• fragmented habitats: isolate species and split populations, reduce ability to adapt

• impact of CC: can increase desertification, increase rate of forest fires, melt polar ice caps

biome shifts caused by climate change

• cause changes in temperature, precip, and weather events can cause biome shifts

• effects: movements of biomes, transformation of existing biomes, loss of unique biomes

impacts of climate change

health impacts

• heatwaves — increased frequency and intensity

• diseases — warmer temp expand habitats for disease-carrying insects

• air quality — poor air quality due to high temp and pollutants

water supply impacts

• droughts — longer and more severe droughts reduce water availability

• melting glaciers — reduce freshwater availability for downstream communities

• flooding — more intense rainfall leads to flooding

• water quality — combined with nutrient pollution, warmer water temp, promotes growth of harmful algal blooms

agricultural impats

• crop yields — changes in temp and rainfall can affect crop production

• pest outbreaks — warmer climates increase prevalence of agricultural pests

• food security — less reliable food supply and higher prices

• livestock — heat stress affects livestock health and productivity

infrastructure impacts:

• extreme weather — can damage infrastructure

• transportation — can damage infrastructure

• buildings — can damage infrastructure

• energy supply — can damage infrastructure

resilience of societies

Resilience refers to a society's ability to withstand, adapt to and recover from climate change impact.

affected by:

• economic stability

• social equity

• adaptive capacity

perspectives on climate change

anthropogenic influence on climate

acceleration of co2 emissions from human activity caused by:

• industrial revolution

• tech advancements

• population growth

analysis of ice cores, tree rings, and sediments

ice cores

• traps air bubbles containing gases from ancient atmosphere

• can show historical co2 levels

tree rings

• thicker rings indicate warmer conditions, could be linked to higher co2 levels

sediments

• deposits in lakes and oceans contain remians of organisms sensitive to env changes — provides indirect evidence of past climates

state sovereignty

it is the principle that each country has the authority to govern itself without external interference

decarbonisation and carbon neutrality

decarbonisation is the reducing or ending the use of fossil fuels that emit co2 when burned. transitioning to renewable neergy sources.

carbon neutrality is achieving net-zero carbon emissions.

• UK: 2050

• china: 2060

• germany: 2045

steps towards decarbonisation

real world example of decarbonisation

climate change mitigation strategies + examples

includes:

• reducing ghg emissions at their sources

• developing techniques to remove ghgs from the atmosphere

climate change adaptation strategies + examples

focuses on reducing the adverse effects of CC and build resilience + adapting to changing climate conditions

what are NAPAs

NAPAs (national adaptation programmes of actions) are plans developed by LDCs to identify and prioritize urgent adaptation needs. ex: bangladesh has implemented NAPA projects to improve flood forecasting and early warning systems.

role of UNDP

UV radiation

the sun emits electromagnetic radiation. shorter wavelengths of radiation have higher frequences = more energy which damages living organisms (eg UV radiation)

UV radiation effects on human health

effects of UV radiation on biological productivity

can lead to:

• reduced photosynthesis rates

• altered plant metabolism

• decreased crop yields

ex: phytoplankton. they act as producers in aquatic food webs. UV radiation can cause DNA damage and reduced photosynthetic activity. reduced phytoplankton productivity can have cascading effects on higher trophic levels like zooplankton.

ozone equilibrium

concentration of ozone in the atmosphere is relatively constant due to steady state equilibrium.

ozone depleting substances and their impacts on equilibrium

ODS are chmicals that can cause stratospheric ozon depletion bcs they destruct ozone molecules (eg aerosols, pesticides, CFCs).

• when ozone equilibrium is disrupted, this leads to increased ozone depletion.

• increased UVB radiation reaches the Earth, which effcts ecosystems and human health.

the montreal protocol

• UNEP played a critical role in the protection of the ozone layer.

• the montreal protocol was initiated in 1987 under the guidance of UNEP.

• the protocol regulates the production, trade, and use of CFCs and ODSs. implementation of ODS alternatives

• regarded as the most successful example of international cooperation in resolving a significant environment

planetary boundary for stratospheric ozone depletion