# Guide

This page is not intended to be modified, and is based directly on the self-study document.

## Card #1 : Human activities

### Description

This is where it all begins...

None

## Card #2 : Industry

### Description

Industry uses fossil fuels and electricity.
It accounts for 40% of greenhouse gas (GHG) emissions.

## Card #3 : Building Usage

### Description

The building sector (housing and commercial use) uses fossil fuels and electricity.
It accounts for 20% of greenhouse gas (GHG) emissions.

## Card #4 : Transportation

### Description

The transportation sector is highly dependent on oil.
It accounts for 15% of greenhouse gas emissions.

## Card #5 : Fossil Fuels

### Description

Fossil fuels are coal, oil, and natural gas.
They are used mainly in buildings, transportation, and industry.
They emit CO2 when burned.

## Card #6 : Deforestation

### Description

Deforestation consists in cutting or burning trees beyond the ability to restore the forest.
80% of the deforestation is related to agriculture.

## Card #7 : CO2 Emissions

### Description

CO2 (or carbon dioxide) is the first anthropogenic (ie linked to human activity) greenhouse gas in terms of emissions.
These emissions come from our use of fossil fuels and deforestation.

## Card #8 : Agriculture

### Description

Agriculture does not emit a lot of CO2, but is responsible for the emission of large quantities of methane
(from cows and rice paddies) and of nitrous oxide (from fertilizers).
In all, agriculture amounts for 25% of GHGs if we include induced deforestation.

## Card #9 : Other GHGs

### Description

CO2 is not the only greenhouse gas (GHG). Among others are methane (CH4 ), and nitrous oxide (N2O),
two gases mainly emitted by agricultural activities.

## Card #10 : Aerosols

### Description

Nothing to do with aerosol spray cans.
Aerosols are a type of local pollution that comes from the incomplete combustion of fossil fuels.
They are bad for human health and they contribute negatively to radiative forcing (they cool the climate).

## Card #11 : Concentration of CO2

### Description

About half of our CO2 emissions are captured by natural carbon sinks.
The other half remains in the atmosphere ; the concentration of CO2 in the air has increased
from 280 to 410 ppm (parts per million) in 150 years.

## Card #12 : Carbon Sinks

### Description

Half of the CO2 we emit every year is absorbed by carbon sinks :
- 1/4 by the vegetation (through photosynthesis)
- 1/4 by the ocean
The remaining half (1/2) stays in the atmosphere.

## Card #13 : Additional Greenhouse Effect

### Description

The greenhouse effect is a natural phenomenon – and incidentally, the first of the GHGs is water vapor.
Without greenhouse effect, the planet would be 33°C colder and life as we know it would not be possible.
But CO2 and other GHGs related to human activity increase the natural greenhouse effect and unbalance the climate.

## Card #14 : Energy Budget

### Description

This graph explains where the energy accumulated on Earth due to radiative forcing goes :
it warms up the ocean, melts ice, dissipates into the ground, and warms up the atmosphere.

## Card #15 : Radiative Forcing

### Description

Radiative forcing represents the difference (caused by humans) between the energy that arrives on Earth each second and the energy that is released.
In the 5 th assessment report of IPCC, it is rated at ${\displaystyle 2.3W/m^{2}}$ (Watt per square meter).

## Card #16 : Melting of Glaciers

### Description

Almost all glaciers have lost mass. Hundreds of them have already disappeared.
These glaciers play a regulating role in the provision of fresh water.

## Card #17 : Increase in Water Temperature

### Description

Oceans absorb 93% of the energy accumulated on Earth.
Their temperature has therefore increased, especially in the upper layers.
The water expands as it warms up.

## Card #18 : Melting of Sea Ice

### Description

Sea ice melting does not make the sea level rise (just as a melting ice cube does not make a glass overflow).
However, when it melts, it gives way to the much darker sea, which goes on to absorb more sun rays than white ice.

### Consequences

• No main consequences

## Card #19 : Melting of Ice Sheets

### Description

Continental glaciers (or ice sheets) are in Greenland and Antarctica.
If they melt completely, they will cause a rise in ocean levels of 7 meters for Greenland and 54 meters for Antarctica.
During the last ice age, ice sheets were so much larger that the sea level was 120 m lower than today.

## Card #20 : Disruption of the Water Cycle

### Description

If the oceans and the atmosphere are hotter, the evaporation that takes place at the ocean surface increases.
This means more rain clouds and more rain. If this happens on land, then the soils dries out.

## Card #21 : Temperature Rise

### Description

Here we are referring to the average temperature of air above the ground on Earth.
It has increased by 1°C since 1900. Depending on the scenarios, the rise in temperature could reach 2°C to 5°C by 2100.
At the end of the last ice age years, the average temperature was only 5°C lower than today... and deglaciation took 10,000 years!

## Card #22 : Sea Level Rise

### Description

Since 1900, sea level has risen by 20 cm.
Sea level rise is caused by the thermal expansion of ocean waters, and the melting of glaciers and continental glaciers.

## Card #23 : Hindered calcification process

### Description

When the pH drops, the formation of calcium carbonate (and more specifically, of calcified shells) becomes more difficult.

## Card #24 : Ocean Acidification

### Description

When CO2 dissolves into the ocean, it turns into acid ions (H2CO3 and HCO3).
The effect of this transformation is ocean acidification (the pH decreases).

## Card #25 : Terrestrial Biodiversity

### Description

Animals and plants are affected by the changes in temperature and the disruption of the water cycle.
They may migrate, become extinct or, more rarely, proliferate.

## Card #26 : River Flooding

### Description

The disruption of the water cycle can bring more water or less water. More water can lead to river flooding.
If the soil has been dried out by a drought, it makes things worse because the water runs off.

## Card #27 : Marine Biodiversity

### Description

Pteropods and coccolithophores are at the base of the ocean food chain.
Therefore, if they disappear, all marine biodiversity is threatened. The warming of ocean waters also threatens marine biodiversity.

## Card #28 : Vectors of Disease

### Description

With global warming, animals migrate. Some of them carry diseases and can reach areas where the population is not immunized against these diseases.

## Card #29 : Pteropods and Coccolithophores

### Description

Pteropods are a kind of zooplankton and coccolithophores a kind of phytoplankton. These organisms have a calcified shell.

## Card #30 : Droughts

### Description

The disruption of the water cycle can bring more water or less water. Less water is a drought. Droughts are likely to become more frequent in the future.

## Card #31 : Freshwater Resources

### Description

Freshwater resources are affected by changes in rainfall and by the disappearance of glaciers that regulate the flow of rivers.

## Card #32 : Decline in Agricultural Yields

### Description

Food production can be affected by temperature, droughts, extreme weather events, floods and marine submersion (e.g. the Nile Delta).

## Card #33 : Marine Submersion

### Description

Cyclones and weather disturbances bring wind (therefore waves) and low pressure conditions.
1 hectopascal less means a 1 cm sea level rise.
Therefore cyclones can cause marine submersions (or coastal flooding), amplified by the sea level rise already caused by global warming.

## Card #34 : Cyclones

### Description

Cyclones use energy from warm waters at the ocean surface. Because of global warming, they are becoming stronger.

## Card #35 : Forest Fires

### Description

Forest fires start more easily during droughts and heat waves.

### Consequences

No direct consequences.

## Card #36 : Heat Waves

### Description

A manifestation of temperature increase is the multiplication of heat waves.

## Card #37 : Starvation

### Description

Starvation can be caused by lower agricultural yields and by the reduction of marine biodiversity.

## Card #38 : Human Health

### Description

Starvation, displacement of disease vectors, heat waves and armed conflicts can affect human health.

## Card #39 : Climate Refugees

### Description

Imagine that you live in a place that has been miraculously spared by climate change. Several billions of human beings might want to share this space with you.

## Card #40 : Armed Conflicts

### Description

This is how we shouldn't let it end...

## Card #41 : Permafrost

### Description

Permafrost is permanently frozen ground.
Permafrost thawing leads to the decomposition of organic matter previously frozen underground, a phenomenon that releases methane and CO2 into the atmosphere.
Beyond +2°C, it is almost certain this phenomenon will accelerate and make the climate spiral out of control.

## Card #42 : Methane Hydrates

### Description

Methane hydrates (or methane clathrates) are a form of ice on the ocean floor, along continental slopes, that traps methane molecules. They can become unstable above +2°C.