earths atmosphere

early atmosphere

• earth was dry and intense volcanic activity = released gases

• mainly Co2 with little to no O2

• volcanoes = water vapour and nitrogen, gradually built up

• small amounts of methane and ammonia

• as earth cooled = water vapour condensed to form the oceans

Global dimming

• Caused by particulates

• These reflect sunlight back into space before it reaches earth

Acid rain

Caused by sulphur dioxide and oxide of nitrogen

today’s atmosphere

• 80% nitrogen

• 20% oxygen

• small proportions of various other gases (argon CO2)

how did Co2 decrease

• as oceans formed:

• Co2 dissolved into them

• dissolved Co2 reacted to form carbon precipitates = it settled as sediment on the seabed = CO2 was locked in sedimentary rocks and fossil fuels

• plants and algae evolved and used Co2 for photo

how did O2 increase

• algae and plants produced oxygen as a byproduct of photo

• Oxygen increased to a level that enabled animals to evolve

greenhouse gases

• water vapour

• Co2

• methane

rising of methane levels

• agriculture

• landfill waste

greenhouse effect

• Short wavelength, radiation from the Sun passes through the atmosphere

• The Earth surface reflects this as long wavelength radiation

• Greenhouse gases absorbed this radiation and reradiated back towards earth

• Warming the surface

human activity of greenhouse gases

• burning fossil fuels

• deforestation

• Driving

• Consuming electricity

global warming vs climate change

• global warming is rise in temp

• it leads to climate change like storms, melting ice caps

carbon footprint definition

total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event

how to reduce carbon footprint

• using renewable energy sources

• Improving energy efficiency

• Carbon capture and storage

• Problem = expensive and requires international cooperation

pollutants

• carbon monoxide

• particulates

• sulfur dioxide

• nitrogen oxides

carbon monoxide

• formed by incomplete combustion

• Problem = toxic gas, it’s colourless orderless and binds to haemoglobin

particulates

• formed by incomplete combustion

• Problem = global dimming and lung damage

Sulphur dioxide

• Formed when sulphur impurities in fuel reacts with oxygen

• Problem = acid rain and respiratory problems

Nitrogen oxides

• Formed when nitrogen and oxygen react in the high heat of engines

• Problem = acid rain and respiratory problems