C13 Flashcards
how long ago do scientists think earth was formed
4.6 billion years ago
what is a theory that suggests how our atmosphere was formed
earths surface was covered in volcanoes and volcanic activity released the gases
what gases did the earths early atmosphere consist of
mainly carbon dioxide
water vapour
nitrogen
how did oceans form
as eath cooled down, water vapour condensed
how long ago do scientists think life began
3.4 billion years ago
what is the % of carbon dioxide in our atmosphere
0.04%
how was carbon dioxide levels slowly decreased
algae and plants by photosynthesis
dissolved in oceans and insoluble carbonate compounds were produced and then these precipitated on the sea bed as sediments
how was coal formed
was formed from thick deposits of plant material
the plant material was buried in the absence of oxygen and compressed over millions of years
what were crude oil and natural gas formed
remains of plankton deposited in mud on the sea bed
these remains were covered by sediments that became layers of rock when compressed over millions of years
the oil and gas were trapped in the rocks
name 3 greenhouse gases
carbon dioxide, methane and water vapour
what is a reason for co2 rise
as temperature risesd carbon dioxide gets less soluble in water which makes the oceans less effective
what is a carbon footprint
carbon footprint of a product or service is the total amount of carbon dioxide and other greenhouse gases emitted over its full cycle
what are actions to reduce carbon footprint
increased use of alternative energy supplies
conserving energy
using carbon neutral fuels
what are some problems with reducing carbon footprint
scientific disagreement over causes and consequences of climate change
incomplete international co-operation on setting targets for the reduction of greenhouse gases
what can incomplete combustion of produce
carbon monoxide
unburnt hydrocarbons
what can particulates cause
cause global dimming as they prevent some sunlight reaching the earths surface
how is sulfur dioxide produced
most fossil fuels contain sulfur compounds
when the fuel burns, the compounds produce sulfur dioxide
what is nitrogen oxide produced
at the high temperatures produced when fuels burn oxygen and nitrogen in the air may combine to form nitrogen oxides
what do sulfur dioxide and nitrogen oxide do
cause acid rain as well as breathing problems
