Natural and anthropogenic causes of climate change Flashcards
what are the four anthropogenic causes of climate change?
Greenhouse gas
Dust and aerosols
Desertification and deforestation
The Ozone Hole
how have Co2 concentrations varied in the last 400 hundred thousands years?
Fluctuated with little ice ages - however, Hockey stick of Co2 concentrations is shown FROM Industrial revolution - JUST BEFORE 1800th century
what was the country in 1995 with the most tonnes per capita of co2 release?
USA - 19.6
how is deforestation affecting climate change?
most of worlds terrestrial carbon stored in forests
forests cover 30% of land surface and hold almost half worlds terrestrial carbon
DEFORESTATION EXPECTED TO RELEASE AN ESTIMATED 87 TO 130 BILLION TONNES OF CARBON BY 2100
greater than 13 years of global fossil fuel combustion
what is the ozone hole?
a region of stratosphere over Antarctic where ozone is depleted
what causes the ozone hole?
suggested that has been caused by CFC’s from refrigeration propellant processes. can persist in the lower atmosphere for decades
so may eventually reach stratosphere
UV light breaks down bonds holding CFC’s together, free chlorine atoms participate in chemical reactions to destroy ozone and return free chlorine atmosphere where it can keep on destroying ozone
what is a kelvin wave
balances coriolis force against topographic boundary such as coastline or waveguide such as the equator
how may volcanoes influence envrionment?
inject sulphur gases intro stratosphere, convert into aerosol. warms stratosphere
more severe at low latitudes
enhance ozone destruction
is there any evidence that sunspot activity affects climate?
conflicting, little ice age in 1450 - 1850, reduced sunspot activity,
but reduced activity in 60s and 70s but no associated lowering of temperature
IPCC concluded solar radiation effect much smaller than greenhouse gas effect
