1. It is a change which is attributed directly or indirectly to human activity
2. that alters the composition of the global atmosphere and which is in addition to
3. natural climate variability observed over comparative time periods”
Human Causes of Climate Change
• Due to an increase in population this means we need to graze more food as the
demand rises. Methane is released by cows although it is a very minor gas it is very
effective in retaining the heat. Since 1950, annual emissions have increased 4
times faster than the increase in C02
• In places like China were an average of 3 coal fire power stations are built, to meet
demands of the economy, carbon dioxide is released when burning fossil fuels e.g.
coal and oil. Fossil fuels have increased atmospheric C02 by 25%
• Deforestation is caused by the need to grow more food and to build houses. This
means more carbon dioxide in the atmosphere as trees generally take in the
carbon dioxide hence contributing to climate change.
The Enhanced Greenhouse Effect
Is the increase in the natural greenhouse effect,
said to be caused by human activities which
increase the quantity of greenhouse gases in the
• Increasing car ownership
• Domestic use
- Power Plants (40% of carbon emissions)
- Cars (33% of carbon emissions)
- Airplanes (causes an estimated 3.5% of global
- Buildings (12% of carbon emissions)
- Deforestation (responsible for 20-25% of
Natural Causes – Changes of Solar
• Solar energy also known as ‘sun spots’
works in cycles, so that the sun’s
energy varies over short periods. This
can increase temperature when there
are more sun spots.
• These cycle last for 11 years
• The darker the spots, the more active
and solar output energy is released.
• Cooler periods, such as the Little Ice
Age, and warmer periods, such as the
Medieval Warm Period, may have
been caused by changes in sunspot
• In 1991, Mount Pinatubo in the Philippines erupted,
releasing 17 million tonnes of sulphur dioxide. This
was enough to reduce global sunlight by 10%, cooling
the planet by 0.5°C for about a year.
• 1815 eruption of Tambora in Indonesia. This was the
biggest eruption in human history. In 1816,
temperatures around the world were so cold that it
was called ‘the year without a summer’, and up to 200
000 people died in Europe as harvests failed. The
effects lasted for four to five years. Sunlight reaching
earth was reduced by 10%.
Variation in The Earth’s Orbit
• According to one theory the Malankovitch
cycles, the Earth’s orbit varies with changes to
the Earth axis every 41 000 years. Theses
variation are thought to be the main cause of
affecting the glaciation cycle.
Climate change can be assessed across short, medium and long timescales.
Short-term (recent) climate change is on a timescale of decades, e.g. global
The medium-term (historical) timescale covers changes over the last few
Long-term climate change has occurred on geological timescales, over
hundreds of thousands to millions of years.
• Globally 87% of energy supplied by fossil fuels
• 79% of people believe the UK should reduce its use of fossil fuels
• Malancvotich discovered that the Earth’s axis has a relation between the sun according to the
earths tilt this affects solar radiation.
• Human activities like burning fossil fuels have threatened species of natural habitats, through
heating of the atmosphere has caused polar environments to melt, making it hard for polar
bears to survive in changing climate condition.
• There is a distinction between the weather and climate. Weather is the short term reference
to atmospheric conditions.
• Fossil fuels are used in transport, domestic homes and come from 48% of cars
• We are dependent on our greenhouse without it the Earth would be 30 degrees colder
• Surface albedo affects climate
• UK has deforested from 90% to 17%
• Sustainability vs cost need to think about adaptation, mitigation or suffer as a consequence.
• Carbon dioxide is likely to remain in our atmosphere for decades
• Indirect impacts of high temperature puts stress on cattle’s because of the infertile land
• Disease patterns like malaria to increase as a result of warm temperature
• Some C02 is absorbed by the oceans this affect marine organism