Session 3 provides students with a detailed understanding of the mechanisms underlying the causes & consequences of climate change, thanks to the workshop called The Climate Fresk.
Past and current consequences in France are detailed in a focus module.
Students end the session by calculating their personal carbon footprint with the workshop Nos Gestes Climat.
Why is a +5°C temperature rise so dangerous?
Over a single day, the temperature can change from 8°C in the morning to 18°C in the afternoon and back to 10°C in the evening: temperature changes are much bigger than +2°C or +5°C.
Weather temperature changes are measured at a specific spot at a specific moment: we experience them everyday.
Climate temperature changes are measured at the global scale over long periods of time: the human body is not equipped to measure them.
Nota bene: it is not because temperature change of weather and climate are measured in °C that they are phenomenon.
An indication of the amplitude of a temperature change of +5°C is to imagine a world were Berlin is below 1km of ice cap, Scandinavia and north of theUK are below 2 km of icecap, the south of France has a comparable climate to that of Siberia today, the Alps are under a huge glacier and oceans are 120m below today's level. That climate was what Europe experienced 20,000 years ago and it was only 5°C colder than today. So how far and how different would another 5°C temperature rise lead us? (based on the pre-industrial climate, 1800).
The second threat is the speed of current climate change: approximately 50x to 100x faster than the last deglaciation as is has taken place over 200-300 years, not 20,000 years.
At that speed, living ecosystems are highly likely to suffer massive damages.
Human activities (transport, industry, agriculture, housing, deforestation, etc.) emit a lot of CO2 into the atmosphere by using massive amounts of fossil fuels (oil, natural gas, coal) as well as other greenhouse gases.
These greenhouse gases generate an additional greenhouse effect increasing the temperature of the air and the oceans which disrupts the water cycle (formation of clouds, rain, etc.).
This disruption of the water cycle has multiple consequences: frequency and intensity of droughts, floods, fires, cyclones, etc. causing drops in agricultural yields and, freshwater reserves and contributing to the disappearance of living species (biodiversity) which can in turn disrupt human activities with consequences such as famines, armed conflicts, human health crises and climate refugees.
The images and texts below are the Wiki of the Climate Fresk.
“CO2 is the main anthropogenic greenhouse gas in terms of emissions (anthropogenic: produced by human activities).
These emissions come from our use of fossil fuels and from deforestation.”
“About half of 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 415 ppm (parts per million) over the past 150 years. This is higher than at any point over the last three million years.”
“The greenhouse effect is a natural phenomenon - incidentally, the most common GHG is water vapor. Without the 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 activities amplify the greenhouse effect and unbalance the climate.”
“Hotter oceans and a hotter atmosphere lead to stronger evaporation, causing rainclouds and rainfall.
Hotter land and a hotter atmosphere also lead to stronger evaporation, this time causing the ground to dry out.”
“Freshwater resources are affected by changes in rainfall and by the melting of glaciers that regulate the flow of rivers.”
“Food production can be affected by temperature, droughts, extreme weather events, floods and marine submersion”
"The disruption of the water cycle can both increase and decrease rainfall.
A lack of rain can cause drought. Droughts are likely to become more frequent in the future."
"Forest fires start and spread more easily during droughts and heatwaves."
"Hunger can be caused by lower agricultural yields and by the loss of marine biodiversity."
"We shouldn’t let it come to this..."
Assigning responsibility to others does not trigger action.