Chapter 2: Variable Weather and Changing Climate

How do human activities contribute to enhanced greenhouse effect?

1. Burning fossil fuels

• The major fossil fuels are oil, coal and natural gas.

• Energy produced from burning fossil fuels is used for industries, transportation, domestic and commercial activities.

• Fossil fuels produce more than 80percent of global energy.

• Fossil fuels contribute to the increase in greenhouse gases.

• The usage of fossil fuels has increased over the years.

Fossil Fuels Consumption

2. Deforestation• Loss of forests due to the removal or clearance of trees in forested

areas.

• Forests absorb millions of tonnes of carbon dioxide every year via photosynthesis, thus taking in a significant amount of global greenhouse gas emissions.

• With deforestation, there are fewer trees and other plants to absorb carbon dioxide.

• Soil is one of the largest sources of carbon in the world.

• Deforestation exposes soil to sunlight.

2. Deforestation• This increases soil temperature and the rate of carbon oxidation in

the soil.

• Carbon oxidation is a process by which carbon in the soil reacts with oxygen in the atmosphere to produce carbon dioxide.

• The greatest loss of forests occur in South America.

• Southeast Asia experiences the second highest rate of deforestation.

• Great losses in forests also occur in Australia and Africa.

• The need for development is the cause for forest clearance.

• To reduce the problem of deforestation, many countries have planted new trees or have imposed laws restricting the trees that have been felled.

3. Changing Land Use • (a) Agriculture

• Is the practice of cultivating land, producing crops and raising livestock.

• Third highest contributor of greenhouse gases.

Tractors run on fossil fuels which release

carbon dioxide.

The use of inorganic fertilisers

increases the amount of nitrous oxide in the soil. Nitrous oxide is

released when soil is ploughed or when rain flows through

the soil.

Organic matter such as dead

leaves and manure releases methane

during decompositionDecomposition is very rapid in rice fields due to a high level of moisture in

the soil.

3. Changing Land Use • (a) Agriculture

• Cattle farming contributes to greenhouse gas emissions because cattle release methane as a waste gas. Millions of tonnes of methane are released each year from cattle farming.

3. Changing Land Use • (b) Industries

• Refers to the production of goods and services within a country.

• Secondary industries which are industrial economic activities such as manufacturing, involve the burning of fossil fuels that result in greenhouse gas emissions.

• Greenhouse gases are also released as by-products when goods are produced.

• Some processes or products result in greater emissions than others.

http://www.theguardian.com/news/datablog/interactive/2012/mar/29/carbon-map-infographic-world?guni=Article:in%20body%20link

http://www.rtcc.org/files/2012/11/carbon-map-for-web.jpg

3. Changing Land Use • (c) Urbanisation

• Is the process by which an increasing number of people live in urban areas such as cities or towns.

• Large amounts of fossil fuels are burnt to provide energy for household activities in urban areas.

• High concentration of cars, buses and other forms of transportation in urban areas also contribute to the amount of greenhouse gases emitted in these areas.

How does climate change affect people?

How does climate change affect people?

Causes

• Sea level rise is the increase in the mean height of the sea’s surface between high tide and low tide relative to land.

• High temperatures cause the melting of glaciers that cause a rise in sea level.

• Higher temperatures in the atmosphere cause water in oceans and seas to expand. This increases the sea level.

Sea level rise Consequences

• 600 million people woldwide live in areas less than 10 metres above sea level.

• Rising sea levels threaten low-lying areas and islands.

• 2/3 of the world’s largest cities in coastal areas are also at risk due to rising sea levels.

http://ens-newswire.com/2013/09/03/10-coastal-cities-at-greatest-flood-risk-as-sea-levels-rise/

How does climate change affect people?More frequent extreme

weather events.Causes

• These include heatwaves, floods, droughts and tropical cyclones.

• Increasing due to higher land and sea surface temperatures.

Consequences

• An extreme weather event is a severe and rare weather phenomenon that results in significant economic losses and loss of lives.

More frequent extreme weather events.

• Case Study – UK

• Examples of extreme weather events in the UK:

• Drought - caused by a lack of rain.

• Flash floods - caused by too much rain in a short period of time.

• Strong winds and storms.

• An extreme cold spell.

• An extreme heat wave.

• All of these have happened in the UK between 2000 and 2010:

• A lack of rainfall leading to drought

• During 2004-06 the UK received below average rainfall. This meant that reservoirs and groundwater supplies were not recharged with the water needed.

More frequent extreme weather events.

• An extreme cold spell

• In December 2010 much of the UK was under snow. Arctic air caused the temperatures to drop significantly below the average. At night temperatures of -10°C were not uncommon.

• An extreme heat wave

• In summer 2003 Europe suffered from an intense heat wave. In the UK the temperature of 38.5°C was the highest ever to be recorded.

• Case study: extreme weather in the UK

• During December 2010 winds from the north east brought cold arctic air and snow. Scotland and North East England were significantly affected, with snow 50 cm deep in places. Temperatures were mainly below 0°C, making it the coldest December in the last 100 years.

• The impacts were:

• Roads were closed. People were stranded in their cars overnight on the M8 and A9 in Scotland.

• Airports closed, including Heathrow and Gatwick, disrupting travel plans over Christmas.

• Schools closed.

• On 20 December the AA reported its busiest-ever day because of car breakdowns.

• More people than usual were admitted into hospital because of accidents and falls.

• Emergency services and local authorities were all put under pressure.

• After areas thawed, there were problems with burst water pipes. In Northern Ireland 40,000 homes were without water.

Case Study – UK

• Flash flooding

• Emergency services on the scene of flooded village of Boscastle

• Boscastle in Cornwall suffered a flash flood in August 2004. Nearly three times the average rainfall for the whole of August fell in just one day. The rain ran down the steep valley sides causing flooding in the village. The floodwater picked up cars and trees in its path.

• Strong winds and storms

• In January 2005 stormy weather brought havoc to roads in the North of England as lorries overturned. Power was also cut off in 80,000 homes. Winds of over 100 mph were recorded.

Emergency services on the scene of flooded village of Boscastle.

How does climate change affect people?Spread of infectious

insect-borne diseases.

Causes

• Climate change could result in increased temperatures and rainfall in various parts of the world.

• Insects thrive in these favourable conditions.

• The distribution of the occurrence of infectious insect – borne diseases is also changing. Regions with moderate temperatures such as Europe and North America are facing diseases once confined to the tropics

Consequences

• Heavy rainfall may allow mosquitoes to grow in numbers in aquatic habitats resulting in the spread of malaria and dengue fever.

How does climate change affect people?

Lengthening the growing season in certain regions. • Higher temperatures may

result in growing season.• The growing season refers

to the period during which crops can be grown.

Advantages

• An increase in the types of crops that can be grown in the United Kingdom.

• New crops such as blackberries and maize can be cultivated.

• The production of fruit, soyabeans, potatoes and wheat is projected to increase in Canada.

Disadvantages

• In the Yunnan province, China, the production of fruits such as apples and cherries and nuts such as almonds and walnuts is reduced as these fruits and nuts require cool weather conditions.

• http://environment.nationalgeographic.com/environment/global-warming/gw-impacts-interactive/