The causes of climate change
The greenhouse effect has existed for millions of years and is essential for life: without it, the Earth would be a frozen planet. The problem is not that it exists, but that we are strengthening it more than the planet can cope with.
The natural greenhouse effect
If you get into a car parked in the sun with the windows closed on a cool day, you notice that the inside is much warmer than the outside, because the glass lets light in but traps heat. Which components of the air do the same job on a planetary scale to stop the Earth from being a ball of ice?
The diagram represents the greenhouse effect in four numbered steps. a) Explain what happens in each of the steps labelled with the numbers 1 to 4. b) Which number…
The diagram represents the greenhouse effect in four numbered steps.
- a) Explain what happens in each of the steps labelled with the numbers 1 to 4.
- b) Which number corresponds to the heat returned by the atmosphere towards the surface?
- c) Name two greenhouse gases.
Explain in your own words what the greenhouse effect is and why it is called that.
Explain in your own words what the greenhouse effect is and why it is called that.
The greenhouse effect is a natural phenomenon necessary for life. Explain why this is so and clarify the current problem (the enhanced greenhouse effect due to human…
The greenhouse effect is a natural phenomenon necessary for life. Explain why this is so and clarify the current problem (the enhanced greenhouse effect due to human emissions).
The human activities that strengthen it
Name three human activities that increase emissions of greenhouse gases into the atmosphere.
Name three human activities that increase emissions of greenhouse gases into the atmosphere.
The concentration of atmospheric $\text{CO}2$ was 317 ppm in 1960, 354 ppm in 1990, and 414 ppm in 2020. Calculate the increase between 1960 and 2020, express it as a…
The concentration of atmospheric $\text{CO}_2$ was 317 ppm in 1960, 354 ppm in 1990, and 414 ppm in 2020. Calculate the increase between 1960 and 2020, express it as a percentage, and relate the trend to human activities.
A car emits about 120 g of $\text{CO}2$ per kilometre. Calculate the emissions of a daily 30 km journey and those of a whole year (250 days), and propose two…
A car emits about 120 g of $\text{CO}_2$ per kilometre. Calculate the emissions of a daily 30 km journey and those of a whole year (250 days), and propose two alternatives to reduce them.
Processes that amplify warming
In the middle of summer, a white T-shirt reflects sunlight and feels cool, whereas a black T-shirt absorbs the radiation and is hot to the touch. What happens at the North Pole when the reflective white ice melts and exposes the dark sea water?
Permafrost, the permanently frozen soil of the Arctic, stores enormous amounts of carbon. Explain what can happen if it thaws and why scientists consider it a process…
Permafrost, the permanently frozen soil of the Arctic, stores enormous amounts of carbon. Explain what can happen if it thaws and why scientists consider it a process that feeds back into warming.
A climate model warns that a 1 °C increase in Arctic water temperature can trigger a positive feedback loop. Design a cause-and-effect flow chart that links in an…
A climate model warns that a 1 °C increase in Arctic water temperature can trigger a positive feedback loop. Design a cause-and-effect flow chart that links in an orderly manner: increase in atmospheric temperature, melting of sea ice, variation in surface albedo, and absorption of solar radiation by the ocean. Based on your diagram, predict what would happen to the planet's thermal self-regulation capacity if the Arctic Ocean became completely ice-free during the summer.
In a school debate, someone argues: «In the Cretaceous there was no ice at the poles and the Earth was much warmer than today without human intervention; therefore, the…
In a school debate, someone argues: «In the Cretaceous there was no ice at the poles and the Earth was much warmer than today without human intervention; therefore, the current warming is natural and we should not worry». Refute this statement by comparing the timescale (rate) at which those geological changes occurred versus that of the current change, and explain what direct consequence this difference in speed has on the adaptive capacity of ecosystems and species survival.