Atmospheric CO2
conc has increased
rapidly since the
mid-19th century
from 280ppm to
nearly 380ppm
CO2 conc is increasing as
more fossil fuels like
coal, oil, natural gas and
petrol are burnt. Burning
fossil fuels release CO2
CO2 conc is also increased by
the destruction of natural sinks
(things that keep CO2 out of the
atmosphere by storing carbon).
They store the carbon as
organic compounds
Methane
Atmospheric CO2 has
increased from 700ppb
during the mid-19th century
to nearly 1700 ppb in 2000
Methane conc is increasing
because more methane is being
released into the atmosphere. E.g
more fossil fuels are being
extracted, there's more decaying
waste and there are more cattle
which give off methane as a
waste gas.
Methane is also being released from
natural stores. As temperatures increase,
it's thought these stores will thaw and
release large amounts of methane.
Increase in human
activities like burning fossil
fuels, farming and
deforestation has increased
atmospheric conc of CO2
and methane. This has
increased the greenhouse
effect and caused a rise in
average global temperature
Introduction
Global warming is the term
for the increase in average
global temperature.
Human activity has caused global warming by enhancing the greenhouse effect
The greenhouse effect is
essential to keep the planet
warm, but too much
greenhouse gas in the
atmosphere means the planet
warms up.
Two of the main greenhouse gasses are CO2 and methane.
Effects of Global Warming
Crop Yield
Increasing CO2 conc could also
be increasing in crop yields
(amounts of crops produced from
an area)
CO2 concentration is a limiting factor for
photosynthesis, so increasing global CO2
concentration could mean crops grow
faster, increasing crop yields.
Insect Pests
May affect the life cycle of some insect species
Increasing temperatures means
some insects go through their
larval stage quicker and emerge
as adults earlier.
Some species are becoming more abundant (e.g.
warmer and wetter summers in some places have led to
an increase in the number of mosquitoes
Other species may become less abundant (e.g. some
tropical insect species can only thrive in specific
temperature ranges, so if it gets too hot fewer insects
may be able to reproduce successfully.
Distribution of wild animals
and plant species
Some species may become more
widely distributed (e.g. species that
need warmer temperatures may
spread further as the conditions they
thrive in exist over a wider area
Other species may become less
widely distributed e.g. species that
need cooler temperatures may have
smaller ranges as the conditions they
thrive in exist over a smaller area.
Climate change could also
affect the number of wild
animals and plants
Some species are becoming more abundant
because the temperatures are rising
Other species are less
abundant (e.g. polar bears
because they need frozen ice
and global warming is causing
more sea ice to melt.