Climate Change

What is climate change?

Large-scale, long-term changes in the average temperatures and weather patterns

How does the Earth's climate change over time?

It changes over time leading to colder and warmer periods

What is the Quaternary period?

The last 2.6 million years with 60 cold periods and warmer interglacial periods

When did the last ice age end?

Approximately 25,000 years ago

What do ice cores trap?

Ash, air bubbles and microbes

What do the air bubbles in ice cores contain?

CO2 providing information about past temperatures

How long do ice cores provide climate information for?

The last 2.6 million years

What historical sources provide evidence of past climates?

Diaries and art such as paintings of the Thames River frost fairs

Why might historical sources be inaccurate?

Because they are subjective

What kind of evidence do paintings and diaries provide?

Evidence seen by people during past colder and warmer periods

What does glacial melting cause?

Sea level rising

What is a modern way of tracking climate change?

Global temperature records

What is the greenhouse effect essential for?

The survival of life on Earth

What do greenhouse gases in the atmosphere allow through to the Earth's surface?

Short-wave radiation from the sun

What do greenhouse gases absorb to help maintain Earth's temperature?

Some of the long-wave radiation

What would the average temperature be without the greenhouse effect?

-18°C

Where does water vapour come from naturally?

Evaporation from the oceans

Where does carbon dioxide come from naturally?

Volcanic eruptions, wildfires and respiration

Where does methane come from naturally?

Oceans, soils, and termites

Where does nitrous oxide come from naturally?

Soils and oceans

What are Milankovitch Cycles?

Long term changes to the Earth's orbit and position

How often does the Earth's orbit change?

Every 100,000 years

What type of orbit is linked to colder periods?

Circular

What type of orbit is linked to warmer periods?

Elliptical

How often does the Earth's tilt vary?

Every 40,000 years

How often does the Earth wobble on its axis?

Every 24,000 years

What happens during large volcanic eruptions?

Vast quantities of ash are ejected into the atmosphere

How does volcanic ash affect temperature?

It blocks solar radiation, causing temperatures to decrease

What are sunspots?

Dark spots appearing on the sun's surface

What is increased sunspot activity linked to?

Higher average temperatures

What do sunspots indicate?

That the sun's effectiveness at radiating heat is increased

How does atmospheric dust from asteroids and meteors affect temperature?

It decreases temperatures

What percentage of global greenhouse gas emissions do fossil fuels account for?

Almost 50%

What are fossil fuels used for?

Transportation, construction, heating, manufacturing, and energy production

How does deforestation for agriculture contribute to climate change?

It reduces the amount of CO2 absorbed during photosynthesis

What uses fossil fuels in agriculture?

The production of fertilisers and pesticides

What increases methane emissions in agriculture?

Raising dairy and beef cattle and rice cultivation

What gas is increased in the atmosphere by artificial fertilisers?

Nitrogen oxide

How does cement manufacturing release CO2?

It is made from limestone which contains carbon

Why has transport emissions increased?

Because of the increasing global population and more vehicles

What fuels do most types of transport use?

Petrol and diesel from oil

What happens in the advanced greenhouse effect when more solar radiation passes through the atmosphere?

The Earth absorbs most of the radiation and warms up

What does the Earth do after absorbing radiation?

It radiates heat energy

What happens to the heat radiated by the Earth?

More of it is absorbed by greenhouse gases in the atmosphere

Why does less heat escape into space in the advanced greenhouse effect?

Because greenhouse gases absorb and radiate the heat

What do greenhouse gases do with the heat they absorb?

They radiate it in all directions

What is the result of the advanced greenhouse effect on the lower atmosphere?

It heats up

What is one impact of climate change on the oceans?

Global sea level rise

How much has the sea level risen since 1880?

Between 20–23 cm

How much does the sea level rise each year?

3.2 mm

How many people could be at risk from sea level rise by 2100?

410 million

Why is climate change causing sea levels to rise?

Thermal expansion, melting glaciers, and melting ice sheets

What is thermal expansion?

Water expanding when warm, increasing ocean volume

How does melting glaciers affect sea levels?

They add water to the seas and oceans

How do melting ice sheets affect sea levels?

They add water to the seas and oceans

What is one social impact of sea level rise?

Displacement of people from their homes and communities

How are food and water supplies affected by sea level rise?

They are threatened by salt intrusion

What can food shortages from climate change lead to?

Malnutrition and famine

What is one environmental impact of sea level rise?

Destruction of ecosystems including coral reefs and mangroves

What is ocean acidification?

A chemical change in ocean water caused by absorption of CO2

What coastal issue increases due to sea level rise?

Coastal erosion

How does sea level rise affect animal life?

It changes patterns of animal migration and behaviour

What is one economic impact of sea level rise?

The cost of building flood defences

Why is relocation costly?

Because new homes must be built for displaced people

How does sea level rise affect tourism?

It reduces tourism due to impact on coastal resorts

Why are the Maldives more at risk from sea level rise?

Over 80% of its islands are less than 1m above sea level

When might the Maldives become uninhabitable if sea levels continue rising?

By 2050

What artificial island has the Maldives built in response to rising sea levels?

Hulhumalé

What has been constructed around some Maldives islands for protection?

Flood walls and defences

What kind of weather changes can climate change cause?

Extreme weather and erratic weather patterns

How do warmer sea temperatures affect storms?

They increase evaporation leading to more frequent and severe storms

What is becoming more common due to rising global temperatures?

Droughts and heatwaves

By 2050, how much higher might average temperatures be in the south-east UK?

Between 2–2.5°

How much more likely are days over 40° predicted to become in the UK?

10 times more likely

What seasonal change is expected for UK winters by 2050?

They will be wetter, especially in the east

How much wetter might some UK areas get in winter?

Over 20% wetter

What seasonal change is expected for UK summers by 2050?

They will be drier

How much less precipitation might the UK get in summer?

20–30% decrease

What is a social impact of extreme heat in the UK?

Increased deaths

Who is most affected by extreme heat?

People with respiratory and heart conditions

What positive social change may occur due to warmer winters?

Fewer deaths from cold

What might affect UK ecosystems due to climate change?

Drought, flooding, and wildfires

Why will wildfires increase in the UK?

Because of drier summer conditions

What environmental change may occur in UK species?

Species changes due to higher temperatures

How might tourism be affected in the UK?

It may increase due to warmer, drier summers

How will climate change affect farming income in the UK?

It may increase due to longer growing seasons

What new crops might UK farmers grow due to climate change?

Citrus fruits and olives

What resource may become less available for farming and power?

Water for irrigation and power stations