Greenhouse gases Evidence of past natural climate change
Causes of CO2: cars, deforestation, power Historical Sources: personal diaries, paintings and religious
stations, burning fossil fuels (89% of records e.g. Anglo Saxon chronicles written by monks from
emissions) around 890 to 1150s which recorded years of drought and heavy
rainfall
Causes of methane: rice fields, cows, peat
bogs, landfill sites, decaying organic matter Tree rings: reveal the history of a tree's growth. in warmer years
(7%) they grow more and there is evidence to suggest climate was
cooler in the past when tree rings were closer
Ice Cores: scientists extract cores of ice from the poles and
within the ice layers show the history of climate change. when
the ice is cut open the gas in the ice can be measured to
compare the greenhouse gases with the temperature at the time
Advantages: gives insight first hand into what the conditions
were like in the past
Disadvantages: could be exaggerated only tells you about
climate in certain places
Greenhouse effect
Evidence human activity is causing climate change
Greenhouse effect: the natural trapping of
the sun's energy in the atmosphere due to • due to the enhanced greenhouse effect global air
the presence of greenhouse gases temperatures are increasing. Between 1901 and
2012 surface temperatures have increased by as
Enhanced Greenhouse Effect: the much as 2.5C in parts of South America
increased greenhouse effect resulting from • upper ocean temperature changes correlate directly
humans emitting more greenhouse gases with surface air temperature change
(from things such as increased car • arctic sea ice has decreased overall from 8 million
ownership and increased demand for km2 to 5.8 million km2 which results in rising sea
natural resources eg wood and coal) which levels
leads to global warming • sea levels have risen by up to 20cm threatening the
existence of many low-lying islands
sea level change • almost all areas of glaciers worldwide are thinning
some as much as 1m/year
highest projection: +0.97m • due to warming seas the destructive power of
lowest projection: +0.28 typhoons has intensified by 50% in the past 40 years
range: 0.97-0.28=0.69 • man-made climate change is responsible for the
increased regularity of extreme heat waves which
Uncertainty: (Why?) are now happening 4 or 5 times as often
• if temperatures rise ice caps • over the last 30 years the number of worldwide
will melt at varying rates and floods has increased due to rising sea levels
produce more water
• when water expands with heat Patterns of long-term climate change
the volume is increased so the
over the last 800,000 years climate has been constantly
sea level will rise (thermal
fluctuating with interglacials only occurring roughly
expansion)
every 100,000 years with glacial periods between them
• factors from temperature
temperatures alternate between warm periods and
change uncertainty could also
cold periods every 400-500 years
affect sea level rise
Causes of CO2: cars, deforestation, power Historical Sources: personal diaries, paintings and religious
stations, burning fossil fuels (89% of records e.g. Anglo Saxon chronicles written by monks from
emissions) around 890 to 1150s which recorded years of drought and heavy
rainfall
Causes of methane: rice fields, cows, peat
bogs, landfill sites, decaying organic matter Tree rings: reveal the history of a tree's growth. in warmer years
(7%) they grow more and there is evidence to suggest climate was
cooler in the past when tree rings were closer
Ice Cores: scientists extract cores of ice from the poles and
within the ice layers show the history of climate change. when
the ice is cut open the gas in the ice can be measured to
compare the greenhouse gases with the temperature at the time
Advantages: gives insight first hand into what the conditions
were like in the past
Disadvantages: could be exaggerated only tells you about
climate in certain places
Greenhouse effect
Evidence human activity is causing climate change
Greenhouse effect: the natural trapping of
the sun's energy in the atmosphere due to • due to the enhanced greenhouse effect global air
the presence of greenhouse gases temperatures are increasing. Between 1901 and
2012 surface temperatures have increased by as
Enhanced Greenhouse Effect: the much as 2.5C in parts of South America
increased greenhouse effect resulting from • upper ocean temperature changes correlate directly
humans emitting more greenhouse gases with surface air temperature change
(from things such as increased car • arctic sea ice has decreased overall from 8 million
ownership and increased demand for km2 to 5.8 million km2 which results in rising sea
natural resources eg wood and coal) which levels
leads to global warming • sea levels have risen by up to 20cm threatening the
existence of many low-lying islands
sea level change • almost all areas of glaciers worldwide are thinning
some as much as 1m/year
highest projection: +0.97m • due to warming seas the destructive power of
lowest projection: +0.28 typhoons has intensified by 50% in the past 40 years
range: 0.97-0.28=0.69 • man-made climate change is responsible for the
increased regularity of extreme heat waves which
Uncertainty: (Why?) are now happening 4 or 5 times as often
• if temperatures rise ice caps • over the last 30 years the number of worldwide
will melt at varying rates and floods has increased due to rising sea levels
produce more water
• when water expands with heat Patterns of long-term climate change
the volume is increased so the
over the last 800,000 years climate has been constantly
sea level will rise (thermal
fluctuating with interglacials only occurring roughly
expansion)
every 100,000 years with glacial periods between them
• factors from temperature
temperatures alternate between warm periods and
change uncertainty could also
cold periods every 400-500 years
affect sea level rise
