Climate and Change Flashcards
Climate Change: Definition
Any change in global temperatures and precipitation over time.
Glacial periods - definition
Time of cooler climate
Interglacial periods - definition
Times of warmer climate.
Ice age - definition
Time that’s colder than a glacial period
Natural causes of climate change - list of theories
- Eruption theory
- Sunspot theory
- Orbital theory (milankovitch cycles)
- Asteroid theory
Natural causes of climate change - eruption theory background
> Big volcanic eruptions can change the Earth’s climate.
Volcanic eruptions produce ash and sulphur dioxide gas. If it rises up high enough it will spread around the stratosphere. The sunlight is reflected back into space, which lowers the average temperature.
Natural causes of climate change - eruption theory examples
- IN 1991, Mount Pinatubo in the Philippines erupted, releasing 17 million tonnes of sulphur dioxide. It reduced global sunlight by 10% by 0.5 degrees for 1 year.
- Mount Tambora, Indonesia - lasted for 2-5 years. One year was without summer.
- 1883 explosion of Krakatoa reduced global temp by 1.2 degrees for at least one year.
Natural causes of climate change - sunspot theory
> The sun’s output is not constant. Cycles have detected reduction in heat.
The temperatures are greatest when there are plenty of sun spots.
It works on an 11 year cycle.
Over 2000 years ago Chinese started to record sun spots.
Natural causes of climate change - orbital theory (Milankovitch cycle)
> It is the changes in the way the Earth orbits the sun.
Cold glacial and ice age were 5-6 degrees colder than today. Some interglacial periods were 2-3 degrees warmer than today.
Every thousands of years.
The Earth’s orbit can change.
The Earth’s orbit can be a circle or an ellipse.
The Earth’s axis can tilt between 22.5-24.5 degrees.
Natural causes of climate change - asteroid theory
> The orbits of some asteroids have the same orbit as the Earth.
Dust and ash smoke from the asteroid which blocks the sunlight making the Earth cold.
It’s very rare for an asteroid to hit the Earth.
If one hits the Earth there is smoke and fire.
Some natural causes of climate change - book
> The Earth’s orbit changes a small amount once every 100,000 years. These are known as Milankovitch cycles.
The amount of energy radiated from the Sun changes over an 11-year cycle.
Volcanic eruptions pump ash dust into the atmosphere causing a cooling effect.
Large asteroid collisions can cause cooling as material blocks out the Sun. Asteroids hitting the Earth can cause huge fires which release massive amounts of CO2 which subsequently has a warming effect,
Ocean current changes can cause cooling and warming. In the UK, we have a warm and wet climate because of warm Atlantic currents. Sometimes the current shifts and we get a cooler climate for a short period of time.
The enhanced greenhouse effect
> Heat (UV rays) from the Sun reaches the Earth’s atmosphere; some is reflected back into space.
The land and oceans absorb the heat.
The land and oceans then radiate infrared heat back into the atmosphere.
Greenhouse gases in the atmosphere trap some of the heat (necessary for life on Earth).
Human activity increases greenhouse gases in the atmosphere leading to more warming.
Humans and climate change
> Global warming is closely associated with rising atmospheric CO2. This is a powerful greenhouse gas and is released by many human activities:
- industry
- transport
- energy production
- farming.
Evidence of human effect on climate change
- Global temperatures are rising - for example in 2015 the average global temperature was 1 degree above the average global temperature in 1850-1900.
- Atmospheric CO2 levels are rising in parallel with global temperatures. This is mostly due to human activity.
- The oceans warmed by 0.11 degrees per decade between 1971 and 2010.
- Sea levels rose globally by about 14 cm during the 20th century.
- Arctic sea ice covers 13% less of the sea each decade.
- Extreme weather events have become more frequent: heat extremes are 5 times more common now than a century ago, for example.
Possible consequences of global warming -8.
- Biodiversity loss on land and in the oceans.
- Coastal flooding from sea-level rises.
- More destruction from more frequent, stronger hurricanes.
- Spread of pests and disease.
- Changes in farming could affect food supplies.
- Loss of glaciers would mean water supply problems in some areas.
- More flood from more frequent, heavier precipitation.
- More droughts, lasting longer.
Why projections for future global temp rises and suture sea-level rises may not be accurate.
> The atmosphere and oceans are highly complex systems.
Computer models can’t always accurately predict how these systems will respond.
For example, the oceans have absorbed more heat than was expected.
Secondly, some natural events are hard to predict.
For example, volcanoes can cause atmospheric cooling and the Sun can enter a cooler phase, affecting global temperatures.
How do we know past climates?
- Ice Cores
2. Tree Rings
studying past climates - ice cores
> I ce sheets contain layers of ice, oldest at the bottom.
Each layer is one year of snowfall.
Trapped in the ice layers are air bubbles.
These preserve air from the time the snow fell.
In air bubbles there’s carbon dioxide particles.
Climatoligists can reconstruct past temperatures by drilling a core through the ice and measuring the amount of CO2 in the layers.
Studying past climates - tree rings
> In temperate climates such as Western Europe, trees grow every summer.
Periods of growth can be seen from the number of rings in a tree- each ring is a year’s growth.
Wetter and warmer = bigger growth.
Trees rarely survive more than a few hundred years, but tree fossils in peat bogs go back thousands of years.
The greenhouse gases
Carbon dioxide
Methane
Nitrous oxide
Halocarbons
Carbon dioxide
> 89% of greenhouse gases produced.
Burning fossil fuels (coal, oil, gas), deforestation which releases CO2.
30% increase since 1850.
Methane
> 7% of greenhouse gases.
Natural gas extraction, landfill, decomposition of organic matter including manure, emission from rice paddy fields.
21 times more powerful than CO2.
250% increase since 1850.
NItrous oxide
> 3% of greenhouse gases produced.
Jet aircraft engines, cars, lorries, fertiliser and sewage farms.
250 times more powerful than C02.
16% increases since 1850.
Halocarbons
> 1% of greenhouse gases.
Used in industry, solvents and cooling equipment.
3000 times more powerful than CO2.
Not natural.
Patterns in pollution
> The smaller population, the less pollution.
More people put a strain on factories, use more cars etc = emissions.
China is the biggest emission releaser in the world.
USA is 2nd biggest emission releaser in the world.
EU, USA and Japan emit 36% of all CO2.
China emits 24%, India and Russia both more than 5%.
What could climate change mean for the UK? cons
> Although richer countries have the technology to help them better adapt to the challenges of climate change, weather patterns become frequently more dangerous.
Main impacts of climate change for UK:
1. Economic costs of migrants who seek refuge in UK.
2. A complete loss of winter sports.
3. Severe storms in winter and longer droughts in summer.
4. More cases of tropical diseases.
5. Major changes for the fishing industry.
What could climate change mean for the UK? pros
> Warmer summers means that growing seasons will be improved in colder parts of the UK.
UKs wine industry will prosper.
Hotter summers could boost tourism and raise the economy.
Specifics - climate change on UK cons
> Scotland’s skiing resorts could be gone by 2050.
Rising sea-levels could bring major erosion to sand dunes near Liverpool.
Temperature increases mean more air conditioning units bought in summer, so more electricity is used all year round.
Temperature increases might mean species patterns may shift and their migration, such as the black grouse disappearing from the highlands.
Specifics - climate change on UK pros
> Hotter summers could boost tourism in towns such as Oxford.
>Growing seasons will be different in Scotland meaning new crops would be grown, improving agriculture.
Extreme weather
> Some scientists think that global warming will result in more extreme weather in the UK. This could mean more:
-heatwaves, like in summer 2033,when the temperature reached 38 degrees.
-flooding, like summer 2007, when parts of the Midlands had a month’s rainfall in 1-2 days.
-storms like the ‘great gales’ in 1987 and 1990, which caused millions of pounds of damage.
Extreme weather is hard to predict. Protecting people from extreme weather is an economic challenge. Cost of insurance will rise. Billions of pounds will need to be spent on new flood defences to protect infrastructure.
Stern Review
> Warned that we should act now to reduce global warming.
We should spend 2% of our GDP reducing greenhouse gas pollution now.
If we don’t do this, the effects of global warming could reduce our GDP by 20%.
-basically ‘spend now, or pay later.’
Bangladesh background
> River brings lots of sediment, which makes excellent fertile soil for farming, down from the Himalayas.
3 major rivers.
90% below 1m above sea level.
One of poorest countries in the world - $550 GDP per year.
One of most crowded places on earth - 147 million people.
Most of Bangladesh’ economical and social activity is based around the river Ganges, an area which is slowly subsiding.
Just a small rise in sea level will have a devastating effect on lives and economy, pushing the poor nation even further down the development scale.
UK has recently donated £75 million in aid, aimed to help Bangladesh adapt to potential changes in sea level.
Where is Bangladesh located?
Southern Asia.
At the foot of the Bay of Bengal.
Why is Bangladesh at risk?
> It’s the world’s 7th most populous country, with 150 million people.
One of the poorest nations with an average income of just over a pound a day.
Vulnerable nation, with much of its land at or near sea-level on the delta of the River Ganges - and this land is naturally sinking and subsiding.
Flooding is already frequent and damaging.
Sea-level rise - affect on Bangladesh
> A small rise in sea-level would leave large areas of Bangladesh permanently under water.
Climate change could also help drive tropical storms further inland, causing more farmers to lose crops (because when storms temporarily raise the water level, sea salt deposits are left behind, killing plants).
Problem of flooding in Bangladesh
> One of the many long-term problems that flooding brings is interrupted schooling when schools are flooded.
If the country is to be lifted out of poverty, then safegaurding education is vital.
Bangladesh needs well-educated citizens if it is to move further forwards.
Aid to Bangladesh
> Britain recently gave £75 million to help Bangladesh tackle the worst impacts of climate change.
Then money will be spent on special adaptation measures to protect schools, rebuilding them on raised stilts and platforms.
Farmers will also be helped with the introduction of crops that are more tolerant to salt.
Quick notes - Bangladesh
> Poorer countries are more vulnerable to natural hazards than rich countries.
Natural hazards, like flooding, an interfere with a country’s long-term economic development.
Climate change means that the risk of flooding and storm damage is increased for Bangladesh.
