7. Fragile environments Flashcards
What are fragile environments?
Natural environments that are sensitive to, and easily abused by, human activities.
eg those at risk from desertification, deforestation and climate change
What is an ecological footprint?
A measure of the mark that humans make on the natural world.
Considers how much land and sea are required to provide us with the water, energy and food we need to support our lifestyle
World: 2ha
UK: 5.5ha
What is desertification?
When once-productive land gradually changes into a desert-like landscape.
Which regions are at risk from desertification?
Western USA and Mexico, Central Asia, North Africa, Middle East
What are characteristics of desertification?
Absence of surface water Soil becomes less usable Increased soil erosion as bare soil is exposed to the wind Increase in salt content of soil Increasing presence of dry, loose sand Lowering of the water table Dried up watercourses and ponds Vegetation becomes degraded or completely lost
What are some natural causes of desertification?
Changing rain patterns: less predictable rainfall and more regular droughts may cause vegetation cover to die, leaving bare soil and triggering desertification
Soil erosion: changing weather patterns can lead to increased soil erosion, reducing support for vegetation growth so vegetation becomes degraded, triggering process of desertification
Changing intensity of rainfall: short intense bursts of rainfall are difficult for the soil to absorb, meaning vegetation may die, triggering desertification
What are some human causes of desertification?
Population growth and immigration: puts pressure on the land to grow more food which can lead to overgrazing
Overgrazing: too much livestock can destroy vegetation by trampling and eating
Deforestation: trees cut down for fuel and housing, roots no longer bind soil, leading to soil erosion
What are some impacts of desertification?
Reduced agricultural output: decline in soil condition plus increasing water shortage lowers agricultural productivity, meaning crops fail and livestock die.
Malnutrition and famine: decline in agricultural output leads malnutrition and then famine, causing starvation and death esp in the young and elderly
Migration: situation may become so bad that people move away in hope of finding somewhere with enough food
What is deforestation?
The cutting down of trees.
Which regions have experienced the most deforestation?
Deforestation has been most severe in the deciduous forests of the warm temperate parts of Europe, China and the USA.
coniferous forests of the cold temperate regions of North America and Eurasia remain relatively untouched.
Alarming speed of deforestation in tropical rainforests (Brazil, Indonesia)
What are characteristics of deforestation?
Clear felling: forest completely cut down
Selective felling: only best trees are extracted so that some trees remain
Recent action: freshly sawn tree trunks and burnt saplings
Longer ago: large fields used to grow crops
What are causes of deforestation?
Agriculture: land cleared for plantations
Commercial logging
Road building
Mining: minerals eg iron, gold and copper
Farming: land cleared to grow own food
HEP: rivers are dammed and huge areas of forest flooded as a result
What are some impacts of deforestation?
Loss of biodiversity: 80% of the world’s species can be found in tropical rainforests, forests provide us with resources eg food, timber, medicines which we must conserve
Climate change: forests absorb carbon dioxide, burning trees also releases CO2, greenhouse gas emissions also contribute to global warming
Economic development: LICs can gain wealth by selling resources, however benefits are only short term unless trees are re-planted, provides jobs and goods from plantations
Increased soil erosion: without tree roots to anchor fertile soil, erosion can occur and sweep soil into rivers, 1/3 of the world’s arable land has been lost since 1960
What is climate change?
Long-term variations in global annual weather patterns.
What are natural causes of climate change?
Milankovitch cycles: variations in the Earth’s orbit around the Sun, which can be changes in the shape of the orbit or the tilt of the axis (obliquity), or wobbles as the Earth spins on its axis (precession)
Volcanic activity or cosmic material: dust and ash ejected into Earth’s atmosphere by eruptions can block solar radiation
What is the greenhouse effect?
The retention of solar radiation (heat) in the atmosphere due to build-up of greenhouse gases.
What are human causes of climate change?
Human activity causes enhanced greenhouse effect
Carbon dioxide: burning fossil fuels, burning trees
Methane: raising livestock and coal mining
Nitrous oxide: car exhaust fumes and using artificial fertilisers
CFCs: released from coolants in fridges, freezers and air conditioners
What are some impacts of climate change?
Rising sea levels: melting of ice sheets and expansion of seawater as it warms, more than 3mm per year, aquifers contaminated so water must be desalinated (economic and social), costal areas flooded (environmental) which may cause forced migration (social)
More hazard events: more extreme weather, warmer seas means more intense storms, 3 day rainfall events increased since 1980, El Niño and La Niña more frequent, more heatwaves, more desertification
Ecosystem changes: push world’s biomes towards the poles, causes some positives such as resources eg oil more accessible and more shipping routes between North America and Eurasia
Reduced employment opportunities: significant amount of economic activity at the coast
Changing settlement patterns: massive migration due to retreat from coastal and low-lying areas, may cause conflict between countries
Health and wellbeing challenges: water scarcity may force us to use contaminated water, increasing water-borne diseases, food supply could be affected
How can we deal with desertification?
Education: teaching people how to make land use sustainable
Reducing soil erosion: plant trees and maintaining permanent plant cover to protect soil from wind
Permaculture: growing a variety of crops in one field
Fuel: don’t use wood as fuel for cooking
Water conservation: use water-spreading weirs
What are water-spreading weirs?
Stone and cement constructions that extend from one side of a valley to another
Reduce speed of water flow, deposit soil, water seeps into ground, water table is raised and extends into cultivable land
How is the Amazon Rainforest managed sustainably?
1965 Forest Code: people who own rainforest land could only clear up to 20% of it, clearing of vegetation prohibited along rivers and on steep slopes
Restoring and replanting (REGUA): Project near Rio de Janeiro is recreating rainforest cover like the original by replanting samplings in deforested areas, hope to restore 12 million ha of land
Soy and cattle moratorium: soy industry pledged not to buy any soybeans produced on Amazon lands, similar rules on cattle
Expansion of indigenous reserves: indigenous people practice more sustainable, small scale cultivation
What should every country do in response to climate change?
Join global effort to reduce greenhouse gas emissions
Protect and conserve forests
Identify fragile environments and decide what should be done to protect them
Identify coastal areas threatened by flooding or marine erosion and decide what action needs to be taken
What was agreed at COP21 in Paris (December 2015)?
Limit global warming below 2℃
The need for global emissions to peak ASAP
All countries must submit a comprehensive national climate action plan
To undertake rapid reductions thereafter in accordance with the best available science
What was agreed at COP26 in Glasgow (November 2021)?
Commitment to limit (phase-down) use of coal and to climate finance developing countries
140 countries pledge to reach net-zero emissions
100 countries (including Brazil) pledge to stop and reverse deforestation
40 countries pledge to move away from using coal
How is the UK government responding to climate change?
Signed Kyoto protocol in 1995, treaty that commits countries to reducing GHG emissions
Climate Change Act (2008) committed to cutting emissions by at least 80% from 1990 levels
In 2019, legislated a target of net zero carbon GHG emissions by 2050
How are UK organisations responding to climate change?
Urban Tree Challenge Fund: aims to plant 130,000 trees across England
Tesco:
Invested over £700mil since 2006
Reduced emissions by 41% per square foot
100% renewable energy
How are UK individuals responding to climate change?
Collective action, eg extinction rebellion Eat less meat, esp beef Insulate homes Solar panels Clean transport Vote for parties against climate change
How is the Chinese government responding to climate change?
Responsible for 22.7% of global GHG emissions, nearly 80% of energy comes from coal
Adopted Paris agreement in 2016
Produced National Action Plan on climate change involving actions which should make China’s economic development more environmentally sustainable
How are Chinese organisations responding to climate change?
Greenpeace East Asia: lobbying China to move away from coal and to invest heavily in renewable energy, get Mainland China and Hong Kong public to take personal action
How are Chinese individuals responding to climate change?
74% of Chinese people surveyed are willing to pay extra for environmentally-friendly products
94% want to remain in the Paris Agreement
37% willing to give up meat
