IB Geography Unit 2 Global Climate Change

Positive feedback loops

The starting point is increased. Eg.

Global temperatures rise → permafrost thaws → permafrost containing CH4 and CO2 release these gasses into the atmosphere → contributes to the greenhouse gasses → enhanced greenhouse effect → global temperatures rise

Negative feedback loops

The starting point is decreased. Eg.

Global temperatures rise → water evaporates more → more cloud cover → more clouds can reflect incoming shortwave radiation back into space → temperatures are lower

What is the natural greenhouse effect

The natural accumulation of gasses in the atmosphere that , when shortwave radiation from the sun comes in, earth absorbs half and emits back long wave radiation, some of this long wave radiation emitted by earth is taken by the greenhouse gasses and reflected back to earth (or through to space). Warms the earth to 18 degrees , opposed to the -15 of the moon without the natural greenhouse effect.

What is the enhanced greenhouse effect

Human activities like increased infrastructure and agriculture lead to the increase of pollutants like CO2 and CH4, which are gasses that accumulate MORE and thus trap MORE of the outgoing longwave radiation and re-emit it back to earth, warming up the earth

How can temperature rise induce climate change

Increase in temperatures = more evaporation of water (from oceans etc.) = more hot air and moisture = more rain and thus floods

Increase temperature can make water evaporate more which can cause more droughts

Hotter air causes more storms more frequently and severly

Ocean acidification

More CO2 into the atmosphere allows for the ocean to absorb more CO2. But, after a while, the accumulating CO2 will make the ocean more acidic because CO2 + H2O → H2CO3 which is an acid. This is bad for aquatic animals that have adapted to the pH of the ocean and very bad for shelled animals relying on carbonate used up by carbonic acid

Climate change effects on animals

Animals can migrate at earlier times due to the temperature increase, expecting it to be spring earlier than it is. When they arrive, the food won’t be ready yet and insects may not be there, so they will be hungry and may not breed as much.

Polar bears are dying due to the lack of sea ice because it’s melting due to the hotter temperatures

Carbon taxes as a means of preventing carbon emissions by market & companies

Carbon credits are permits that allow the emission of 1 tonne of CO2. Companies are allowed a certain number of carbon credits, and if a company wants more credits then they will have to pay for them. If a company emits less than they are allowed, they can sell their credits to another company. This is meant to encourages lower CO2 emissions since companies wouldn’t want to pay extra, but some companies are very wealthy and don’t care. Also, carbon credits can be GIVEN if a company does something that prevents or reduces CO2 emission, like planting a bunch of trees or start renewable energy projects. This, however, can allow the company to do something really phony/not big and greenwash - pretending to be more eco friendly than they actually are.

Exposure

The degree to which people are exposed to climate change (eg. people in low lying areas are more exposed, or people in drought-prone areas)

Sensitivity

The degree to which people will be harmed by exposure to climate change (eg. LICs have a much higher sensitivity because they don’t have so many mitigation strategies and are less able to adapt or cope with these hazards. Also may be more reliant on sectors more sensitive to climate change eg. agriculture can be affected by droughts/flooding, thus affecting people who rely on it)

Adaptive capacity

The degree to which people can decrease the potential harm of climate change by reducing their exposure or sensitivity (eg. higher income countries can adapt more due to their resources, making them less exposed by building more dykes/investing in more geoengineering things)

Geo-engineering for climate change mitigation

Afforestation - the building of more forests allows for more CO2 to be absorbed rather than accumulate in the atmosphere into greenhouse gasses

Space mirrors - mirrors in space that reflect the incoming short wave radiation back out into space, preventing it from being absorbed by earth and heating it up

Injecting aerosols into the air - Aircrafts release aerosols into the air, which accumulate with water vapor and form a lot of little clouds, which reflect incoming solar radiation and thus prevents the earth from absorbing it, cooling the earth

Carbon capture & storage - Carbon is captured from the air and then stored underground in rocks, reducing CO2 in the air and thus less greenhouse gasses = less warming

Global dimming

Pollution and aerosols (also contrails from airplanes) are added into the air. The particles scatter, accumulate with water vapor, and form many small clouds with a high surface area, more able to reflect incoming shortwave radiation back into space. This leads to less incoming radiation to earth, so the temperatures are lowered. The day on and after 9/11, when there were less planes in the sky, the temperatures increased due to less contrails.

Also can happen due to volcanic eruptions in the sky, eg. Mount Pinatubo erupting in 1991 which decreased temperatures in the area because of the heavy sulfur and ash in the air.

It hides the effects of climate change, not prevents it.

Bangladesh as a case study

Vulnerability:

Most of Bangladesh is on a low lying delta, formed by nearby rivers eg. the Ganges

It is exposed to frequent monsoon rainfall

It is already vulnerable but now there’s sea level rise and more climate change = more rivers overflowing

Many people live on the delta and floodplains, very high population density. Also the housing materials is very bad since people have lower incomes around here, since it’s mostly fishermen and agricultural workers.

Impacts on flooding:

Monsoon rainfall is predicted to be even worse, which would increase flash floods and hurt people.

Social - Many deaths, peoples houses being destroyed, more water-borne diseases, farms etc. being flooded and agriculture unable to be grown, people needing to be displaced.

Environmental - More flooding = more water contamination and affects vegetation.

Management/responses:

Flood shelters on stilts, a lot of embankments built to prevent water from flooding into the nearby villages, drainage channels to remove excess water, etc.

Adaption vs Mitigation

Adaption is when humans deal with the effects of climate change (eg. building houses on stilts), and mitigation is when humans tackle the root cause of climate change by reducing GHG emissions or increase carbon storage to stop global warming.

Human factors that increase climate change vulnerability

Poor housing materials make people more sensitive to physical damage from floods and severe weather events, leaving them to be displaced or harmed

Building houses in low lying areas can make them affected by flooding, leaving them harmed/displaced

Poverty is usually associated with less education about climate change so they’d be more sensitive to it since they don’t know how to deal with it

Dependance on agricultural sectors for income - flooding/droughts can affect agriculture and thus the income of that person