The evolution of the atmosphere (P2) Flashcards
(19 cards)
Explain phase one of one theory of the formation of earth’s atmosphere.
The first billions years, intense volcanic activity that released gases: carbon dioxide, nitrogen, water vapour, methane and ammonia.
.Similar to atmospheres of Mars and Venus
Explain how carbon dioxide decreased.
.Water vapour in the atmosphere condensed to form the oceans which dissolved lots of carbon dioxide in the oceans
.This dissolved carbon dioxide when through reactions to form carbonate precipitates that formed sediments
.Plants and algae absorbed carbon dioxide so they could carry out photosynthesis
.When marine animals, plants and plankton die, over millions of years, they form sedimentary rocks, oils and gas that trap the carbon within them
-Fossil fuels made like this, crude oil from plankton, coal from plant deposits, limestone from calcium carbonate deposits from the shells of skeletons and shells of marine animals
Explain how oxygen increased and the effects.
.Plants and algae produce oxygen from photosynthesis
.Algae evolved around 2.7 billion years ago
.As oxygen levels built up, more complex life could evolve
Composition of atmospheric gases 200 million years ago (similar to today)
Around 80% nitrogen
Around 20% oxygen
Small amount of other gases e.g. carbon dioxide, noble gases and water vapour
Give 3 examples of greenhouse gases.
Carbon dioxide, methane, water vapour
Explain the greenhouse effect.
- Greenhouse gases don’t absorb short wavelength from the sun but absorb long wavelength radiation that gets reflected back off earth
2.Then they re-radiate it in all directions- including back towards earth - Longwave radiation is thermal radiation so results in the warming of the earth
Give ways that humans are affecting the amount of greenhouse gases in the atmosphere.
Deforestation: .fewer trees mean less CO2 is removed from atmosphere via photosynthesis
Burning fossil fuels: carbon that was ‘locked up’ in these fuels is released as CO2
Agriculture: more farm animals produce more methane through their digestive processes
Creating waste: more landfill sites and more waste from agriculture means more C02 and methane released by decomposition of waste
How reliable/ true is the theory of climate change?
Most scientists agree that extra carbon dioxide from human activity is causing this increase and that this will lead to climate change.
.Evidence has peer reviewed making the information reliable
But…
.Earth’s climate so complex and there’s so many variables, that it’s very hard to make a model that isn’t oversimplified
-led to speculation, particularly in media, people saying that we only have some of the information
Effects of climate change.
.Temperature increased can lead to melting polar ice caps meaning sea levels rising which can result in flooding in coastal areas
.Change in rainfall rainfall patterns may cause some regions to have too much or too little water. This can affect the ability of certain regions to produce food
.Changes in temperature and water availability in a habitat may affect wild species, leading to differences in their distribution
What is carbon footprint?
Measure of the amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, event or service.
.Gives a rough calculation of what the worst emitters are
Give ways to reduce carbon dioxide.
.Renewable energy or nuclear energy instead of fossil fuels
.Government could tax companies or individuals based on the amount of greenhouses they emit, e.g. taxing cars based on the amount of carbon dioxide they emit over a set distance so people choose more fuel efficient ones
.Governments can put a cap on emissions of all greenhouse gases companies make0 then sell licences for up to that cap
Why might actions to reduce carbon footprints limited?
.A lot of governments are worried that making these changes will impact economic growth particularly for developing countries
-countries don’t want to sacrifice their economic development if they think other countries won’t do the same
.Individuals won’t change if there is not enough education about why changes necessary and how to make them
Explain how the combustion of fossil fuel produces waste substances.
Fossils, such as crude oil and coal contain hydrocarbons. The carbon and hydrogen are oxidised so that carbon dioxide and water vapour are released into atmosphere when they undergo complete combustion.
If there’s not enough oxygen, they undergo incomplete combustion. Particulates of soot (carbon) and carbon monoxide as well ad carbon dioxide.
Explain a problem of particulates.
If inhaled, they can get stuck in the lungs and lead to respiratory problems.
Explain problems of carbon monoxide.
.Binds to haemoglobin that normally carries oxygen so less oxygen is transported around the body
-lack of oxygen in the blood can lead to fainting, a coma or even death
.It’s colourless and doesn’t have a smell so dangerous
Explain the cause of acid rain.
.Sulfur dioxide is released during combustions of fossil fuels that contain sulfur impurities- the sulfur in the fuel becomes oxidised
.Nitrogen oxidised caused by the heat of burning
.When these gases mix with clouds, they form dilute sulfuric acid and dilute nitric acid which falls as acid rain
What are the effects of acid rain?
Acid rain kills plants and damages buildings.
What are the negative effects of sulfur dioxide and nitrogen oxides?
They can cause respiratory problems if breathed in.
