Global Warming Facts
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1/ What is global warming?
warming is the warming up of the planet above the temperature
it "should" be. It is such a concern at the
moment as it seems that the temperature is rising at a rate
far faster than ever before and it is thought that it may
be the activities of the human population over the last
150 years or so that is doing it.
Mean temperatures over the
whole planet have risen by about 0.74° C (1.33°
F) in the last 100 years. More than half of this increase
has happened in the last 25 years. The temperature records
used to calculate this are extensive, they have been assembled
from thousands of observation sites on land and sea covering
a large, representative portion of the Earth's surface.
Checks and allowances have been made for any bias that may
have arisen from the weather stations or instrument changes.
This is a worry
because while the planet can cope with changes in temperature
which are known to have happened over periods of
tens and hundreds of thousands of years in the past and
certainly over millions of years, we don't know how
it will cope with relatively rapid changes in temperature.
The current rate of change is much,
much faster than any changes have ever before as far
as we are aware and this is a real problem as while animals
and plants can adapt to slow changes by migration for instance,
a rapid change will inevitably lead to large extinctions
of many species. The human population of the earth is also
dependent on a stable climate for established agriculture
and also cities, millions if not billions of people stand
to suffer from the consequences of global warming mainly
the most vulnerable people in the undeveloped nations (ref).
Climate changes in the past over Geological
time periods (millions and tens of millions of years) have
been very drastic. During cold periods, much of the
planet, even thousands of miles from both poles have been
ice-covered by huge glaciers. During warm periods, the same
regions may have been sub-tropical or even tropical. Accompanying
this have been large changes in sea-level so that some areas
of land have either become flooded completely or left high
It is potentially an enormous problem
as if the global temperature rises to a level where it is
affecting the Antarctic ice-caps, they may begin to
melt and cause sea-level rises globally measured in meters.
There are a great many cities around the world that are
on the coast and they would be flooded and probably have
to be abandoned. There are also a great many countries,
especially poorer countries where a large part of the population
live in coastal regions. In this case the farm-land would
be flooded and the people left homeless and without the
ability to feed themselves. In some cases entire island
nations (albeit small ones) in the Pacific Ocean could simply
There are two questions about Global Warming
that the world has at the moment and neither of them has
a clear answer, there is much scientific debate and an awful
lot of political argument too.
1/ If Global Warming is the result
of man's activities:
- How do we stop it?
- Whose responsibility is it
to stop it?
- Can we stop it?
2/ As Global Warming is taking
place, regardless of the cause:
- How do we deal with it's
2/ How do we know that global warming
has taken place?
We know that global warming has taken place because millions
of temperature measurements have been taken over many decades
from all points on the earth.
The measurement of global warming is of a wide variety of
statistics over a period of time and therefore can be quite
difficult to explain and understand.
The global average air temperature
shows a linear trend of 0.74 [0.56 to 0.92] °C for the
100-years from 1906-2005
This sounds like a small
increase and is easily misinterpreted
For example some would say
that when 2006 is described as being "the hottest in
Britain since 1659" (when temperatures began to be
recorded in central England) it simply means that
it was as warm in 2006 as it was in 1659 and there wasn't
any worry about global warming then, so why is there now?
Hottest since 1659 means
that was when temperatures started to be recorded - not
that 1659 was the 2nd hottest year ever.
Past record years have come
pretty much at random and certainly not in groups. The fourth
hottest year in Britain since 1659 was 1949, 8 of the 10
hottest years since 1860 have all occurred in the last decade.
Daily variations in temperature
can commonly be from 5°C
which makes the average
0.74°C rise difficult
to spot by the individual in the shorter term.
of the world are showing the effects of warming more than
others. The Northern hemisphere for instance appears to
be warming more than the Southern hemisphere, possibly because
there is more land in the north and more sea in the south
Northern hemisphere average
annual temperatures compared to the 1961-1990 average
3/ How does global warming affect our
It is difficult to say specifically what the current effects
of global warming are as the weather over much of the globe
is subject to large natural variations.
We cannot say categorically that a particular storm or event
such as hurricane, tornado, flood etc. is a result of global
warming because these things have always happened and there
have always historically been years when there have been
more or less of them than the average.
These are some of the effects that have been observed in
Studies suggest that the ranges of
plant and animal species are shifting towards the poles
at around six kilometres a decade.
of heavy precipitation events has increased over most
land areas - consistent with warming and increases
of atmospheric water vapour.
Greater prevalence of floods.
Drying in the
Sahel, the Mediterranean, southern Africa and parts
of southern Asia.
Crop failures and increased regional
and longer droughts observed since the 1970s, particularly
in the tropics and subtropics.
- Crop failures.
Arctic sea ice extent shrunk by 2.7 % per decade,
decreases in summer 7.4 %
- Effects on wildlife, particularly polar bears.
Significantly increased precipitation
in eastern parts of North and South America, northern
Europe and northern and central Asia.
Greater prevalence of floods.
Temperatures at the top of permafrost layer have
generally increased since the 1980s by up to 3°C
Buildings and roads subside and ecosystems are altered
across the arctic from Alaska to Canada and Russia.
cold nights and frost less frequent.
Hot days, hot
nights, and heat waves more frequent.
evidence for an increase of intense tropical cyclone
activity in the North Atlantic since about 1970,
correlated with increases of tropical sea surface temperatures.
Glacier retreat since
These aspects of climate have
not been observed to change
Increased incidence of
Increased incidence of
Increased incidence of
Increased incidence of
Melting Antarctic sea
4/ How will global warming affect our
The predicted effects of global warming
will mean that more of what would have been "normal"
storms become more destructive, heavy rainfall becomes very
heavy rainfall, short droughts become longer droughts etc.
extreme weather events will become more common
The worst potential effects of global
warming are probably a result of melting of icecaps so causing
global sea-levels to rise and flood many low-lying areas
of the world including major cities and agricultural areas.
The extent to which this might happen is dependent on how
much the temperature may rise and this is the most difficult
One of the currently most regarded
estimates for this future warming is 1.8°C
- this is in addition to warming that has already happened.
is however the possibility that this could be anywhere from
a possible 1.1°C to as high as 6.4°C.
This warming effect is
expected to be greater in the Northern than the Southern
hemisphere and to become more pronounced at higher northern
These are some of the predicted
effects for the future.
in thaw depth most permafrost regions.
Sea ice is projected
to shrink in both the Arctic and Antarctic.
In some projections,
Arctic late-summer sea ice disappears almost entirely
by the latter part of the 21st century.
Very likely that hot
extremes, heat waves, and heavy precipitation events
will continue to become more frequent.
that future tropical cyclones will become more intense,
with larger peak wind speeds and more heavy precipitation.
and sea level rise would continue for centuries
due to the timescales associated with climate processes
and feedbacks, even if greenhouse gas concentrations
were to be stabilized.
Temperatures in excess
of 1.9 to 4.6°C warmer than pre-industrial sustained
for millennia - Ževentual melt of the Greenland ice
sheet. Would raise sea level by 7m. Comparable to
125,000 years ago.
Snow cover is projected
5/ How can we help reduce the effects
of global warming?
It's about cutting power use and
consumption generally - not so simple in a world where
consumption is often admired and sometimes envied and where
power use can make life more convenient or more interesting.
As a rule of thumb though anything you
can do to use less energy and buy
locally produced items of quality rather than
cheap and cheerful in quantity will help. There are many
guides as to what to do, some very effective, others less
so, the most effective are:
- Get a less polluting car and
use it less often.
- Get more efficient refrigeration
- fridges and freezers are on 24/7/365 and as a
result use the most energy of any domestic appliance.
- Reduce the amount of heating your
house or office needs, use insulation, stop draughts,
turn the thermostat down 1 degree.
- Reduce water heating requirements,
takes showers not baths, take normal showers, not
power-showers, get a more efficient washing machine.
- Get low energy light bulbs
and turn them off when not needed.
- Fly less or not at all.
6/ How does global warming lead to
weather is the result of the effect of heat energy coming
from the sun combined with the atmosphere and oceans and
the fact that the earth is rotating about its axis and around
Different parts of
the earth heat up and cool down at different times of the
day and year depending on incoming radiation, this causes
air and water to move as winds and currents. In other words,
the energy from the sun stirs up the earths atmosphere and
oceans and causes what we call "weather".
The greater the amount of heat that arrives
or gets kept behind means that the weather becomes more
energetic. Global warming means more energy is retained
by the earth to power the weather, so we are likely to get
more frequent and more extreme weather conditions as various
kinds of storms as this energy dissipates within the atmosphere.
Global Warming |
GW Antarctica |
Carbon sinks |
Carbon cycle |
Carbon Offsetting |