Climate change Flashcards
What is climate change?
A long term shift in the planets weather pattern or average temperatures
What is the quaternary period?
The last 2.6 million years of earth’s history
What is the Holocene period?
11,700 years ago to today
What is Pleistocene?
26 million years ago to 11,700 years ago
What were the colder periods called?
Glacial
What were the warmer periods called?
Interglacial
What is an ice age?
A period of long term reduction or increase of the temperate in the earth’s surface and atmosphere creating polar ice sheets
Where can we find evidence of an ice age?
- Northern & southern hemisphere
- Antarctica, North of North America, North of Europe, North of Asia
- Chile = Andes, Nepal, Himalayans
Name the evidence of climate change.
- Fossil Evidence
- Ice cores
- Historical records
- Ocean sediment
What does fossil evidence show us?
Climate from millions of years ago
What is the disadvantage of fossil evidence?
It is difficult to be precise
Give an example of fossil evidence.
Crocodile from 60 million years ago in North Dakota
What does ocean sediment show us?
The sediment has oxygen isotopes in them and scientist use them to calculate the change in atmospheric temperature
What do ice cores show us?
The temperature of the atmosphere from the past 400,000 years
What’s a disadvantage of ice cores?
Cannot look at older dates because there’s no ice old enough on the planet
Give an example of ice cores.
In Antarctica, the ice sheets are 5km deep in some places and the ice dates back to 800,000 years ago
What do historical records show us?
The climate at the time
What’s a disadvantage of historical records?
Can be very inaccurate because we can’t tell if it was consistent or for one day
Give an example of historical records.
cave paintings from 4000 years ago
Diaries
Records
Give some recent evidence of climate change.
- Global temperature data
- Ice sheets and glaciers
- Sea level change
How much has global temperature increases since 1950?
0.6°C
What evidence shows glaciers and ice sheets are melting?
Maps and photos
How much has the arctic sea declines in the last 30 years?
10%
What effects have happened because of shrinking glaciers and ice sheets?
- Increasing wildfires
- species going extinct
- effects habitats causing food changes
How much have sea levels rising over the last 100 years?
10 -20 cms
What cause seas levels rise?
The additional water from fresh ice and thermal expansion of the ocean due to higher temperatures
Name the 3 natural climate change theories
- eruption
- sunspot
- orbital
How does the eruption theory change the earth’s climate?
Big eruption
Describe the eruptional theory.
Volcanic eruptions produce ash, sulphur and dioxide gas.
High winds spread them around the earth’s stratosphere.
The ash and gases will stop sunlight from reaching the earth’s surface.
It’s reflected back into space.
This lowers the average temperature
How long does the effect of the eruption last?
1 year
Give an example of an eruption?
Mount Pinatubo Released 17 million tonnes of sulphur dioxide Decreased sunlight by 10% For about a year Decreased planets temperature by 0.5°C Decrease rainfall by 3% in Indonesia
What is the sunspot theory?
Black areas on the sun’s surface indicate the sun is more active than usual.
Lots of spots indicate lots of solar energy fired towards the earth.
How long does the effect of the sunspots last?
11 years
What is the orbital theory?
When the earth tilts on its orbit it also wobbles changing the way the sun hits the earth
How long is the effect of the orbital theory?
Thousands of years
