The Changing Earth - "The climate has always changed .......what is all the fuss about?"
The climate has changed before.
When people say "It's changed before without people, so people can't be involved this time" ....think of forest fires.
Fires happened throughout time, does that mean people can't start fires?
Ice ages, warm times ... the geological record in the rocks shows many events.
Even so, the current changes are very unusual.
Fires happened throughout time, does that mean people can't start fires?
The recent rise in temperature is very fast.
What other kinds of changes are happening?
Geologists have compared the past with the present.
This report -
Climate Change Evidence: The Geological Society of London
explains what they have discovered.
This is based on part of that report:
"Before the current warming trend began, temperatures were declining.
This cooling took Earth’s climate into the ‘Little Ice Age’ (1450 – 1850).
Calculations indicate that this period of cool conditions should continue for about another 1,000 years.
Nevertheless, after 1900 the overall decline in temperature sharply reversed."
So the Earth should be cooling.
There's lots of evidence for human involvement in these changes.
Atmospheric CO2 is now around 400 parts per million (ppm).
It last reached similar levels during the Pliocene, 5.3-2.6 million years ago.
In the middle Pliocene, the concentration of carbon dioxide in the air ranged from about 380 to 450 parts per million.
During this period, the area around the North Pole was much warmer and wetter than it is now.
Summer temperatures in the Arctic were around 15 degrees C, which is about 8 degrees C warmer than they are now.
Global average temperatures were 2-3°C warmer than today.
Sea level rose by up to 20 metres in places.
What are the risks?
This source gives examples relating mainly to the USA ..........
but applicable more widely too.
For more interesting information, see -
Fact Sheets produced by
What other kinds of changes are happening?
Geologists have compared the past with the present.
This report -
Climate Change Evidence: The Geological Society of London
explains what they have discovered.
This is based on part of that report:
"Before the current warming trend began, temperatures were declining.
This cooling took Earth’s climate into the ‘Little Ice Age’ (1450 – 1850).
Calculations indicate that this period of cool conditions should continue for about another 1,000 years.
Nevertheless, after 1900 the overall decline in temperature sharply reversed."
So the Earth should be cooling.
There's lots of evidence for human involvement in these changes.
explains what they have discovered.
This is based on part of that report:
"Before the current warming trend began, temperatures were declining.
This cooling took Earth’s climate into the ‘Little Ice Age’ (1450 – 1850).
Calculations indicate that this period of cool conditions should continue for about another 1,000 years.
Nevertheless, after 1900 the overall decline in temperature sharply reversed."
So the Earth should be cooling.
There's lots of evidence for human involvement in these changes.
Atmospheric CO2 is now around 400 parts per million (ppm).
It last reached similar levels during the Pliocene, 5.3-2.6 million years ago.
In the middle Pliocene, the concentration of carbon dioxide in the air ranged from about 380 to 450 parts per million.
During this period, the area around the North Pole was much warmer and wetter than it is now.
Summer temperatures in the Arctic were around 15 degrees C, which is about 8 degrees C warmer than they are now.
Summer temperatures in the Arctic were around 15 degrees C, which is about 8 degrees C warmer than they are now.
Global average temperatures were 2-3°C warmer than today.
Sea level rose by up to 20 metres in places.
Sea level rose by up to 20 metres in places.
What are the risks?
This source gives examples relating mainly to the USA ..........
but applicable more widely too.
For more interesting information, see -
Fact Sheets produced by
Fact Sheets produced by
