Carbon cycle EQ3

Question 1

What is causality?

Answer 1

The causes of changes to the water and carbon cycles brought about by human activity.

Question 2

What are systems?

Answer 2

The ways in which ecosystems respond to change.

Question 3

What is resilience?

Answer 3

The impacts of human activities on the resilience of natural systems.

Question 4

What are the 4 ecosystem services?

Answer 4

• Supporting services.
• Provisional services.
• Regulating services.
• Cultural services.

Question 5

What are supporting services?

Answer 5

These keep ecosystems healthy by providing other services, like soil formation, photosynthesis, nutrient cycling.

Question 6

What are provisional services?

Answer 6

These are the products obtained from ecosystems, including fibre, fuel, genetic resources and natural medicines.

Question 7

What are regulating services?

Answer 7

Benefits obtained from the regulation of eco systems processes, including regulating air quality.

Question 8

What are cultural services?

Answer 8

Non material benefits that people obtain from eco systems such as spiritual well being, recreation and science.

Question 9

What is grassland conversion?

Answer 9

Temperate and tropical grasslands have also become heavily exploited by agriculture. Both grassland types have suffered as a result of overexploitation. The simple act of ploughing leads to an immediate loss of both carbon dioxide and moisture, as well as a change in runoff characteristics.

Question 10

Why has there been a conversion of grassland to farmland?

Answer 10

Farmers have been encouraged to grow corn, soya and sugar cane to be used to make biofuels. This is very profitable. 5.5 million hectares of natural grassland disappeared.

Question 11

What are the benefits of growing natural grassland?

Answer 11

• Traps moisture and floodwater.
• Absorbs toxins from soils.
• Act as a carbon sink.
• Acts as a terrestrial carbon store.
• Provides cover for dry soils.

Question 12

What are cons of converting grassland into biofuels?

Answer 12

• Removal releases co2 from soils.
• Annual ploughing enables soil bacteria to release co2.
• The lung effect is reduced.
• Biofuel crops are heavy consumers of water, and need irrigation.

Question 13

How has deforestation impacted the carbon cycle?

Answer 13

• The clearance of forests both for their timber and for the land they occupy. In the latter case, the land is mainly cultivated to provide grazing for livestock or to produce cash crops. However, it is not all bad news, as afforestation and reforestation are underway in temperate latitudes. This is helping to offset the loss of tropical rainforest ‘services’, but in the case of afforestation, much is taking place on what was agricultural land.
• There has been a net gain of more than 500,000 ha of forest area in China for 1990-2015, as well as gains of 250,000-500,000 ha in the USA and India. A net gain of 50,000-250,000 was experienced in Russia, Turkey, Iran, Italy, France and Spain.
  There was little change in the rest of Europe, northern Africa and the Middle East and the remainder of Central Asia. However, there were losses in South America, Central Africa, and Australia, and losses of more than 500,000 ha in Brazil and Indonesia.

Question 14

How does deforestation affect the water cycle?

Answer 14

• Infiltration decreased.
• Flood peaks are higher.
• Increased river discharge.
• Reduced rainfall.

Question 15

How does deforestation affect the soil

Answer 15

• CO2 is released.
• Biomass is lost which is due to reduced plant growth.
• Coarser and heavier sands.

Question 16

How does deforestation affect the atmosphere?

Answer 16

• Oxygen is reduced due to lower transpiration.
• Air is dryer.
• Turbulence is increased as the ground induces air currents.

Question 17

How does deforestation affect the biosphere?

Answer 17

• Less CO2 absorbed so there’s reduced carbon stored.
• Species diversity is reduced.
• Biomass is lost due to reduced plant growth.

Question 18

How has urbanisation affected the carbon cycle?

Answer 18

• No land-use conversion is greater than that associated with urbanisation. Much space has already been taken over and many ecosystems completely destroyed by the insatiable demand for space needed to accommodate a rapidly rising urban population and their widening range of economic activities. Of all forms of development, none is having a more disruptive impact on the carbon and water cycles than urbanisation. Towns and cities are focal points of both GHG emissions and intense water demand.
• Clearly, these changes vary from place to place and as a consequence so does their overall impact on carbon stores, soil health and the water cycle. In some locations, the impact is considerable, in others, it is minimal if at all.
• Urban areas account for more than 70% of CO2 emissions from burning fossil fuels. Urban expansion in the tropics is responsible for 5% of the annual emissions from land use change.
• Low-density suburban sprawl with little public transport and homes far from work and shops means more cars on the roads emitting carbon dioxide. In addition, most of the ever-increasing number of buildings still use fossil fuels for their energy needs
• Around the world, only 2% of the Earth’s land area is urbanised. However, these urban areas are responsible for the release of 97% of anthropogenic carbon dioxide emissions.

Question 19

What is ocean acidification?

Answer 19

Oceans are carbon sinks and as C02 in the oceans increases the PH decreases. It becomes more acidic. This means it cant absorb alkaline calcium acidification. The ocean is 30% more acidic than it was in 1750.

Up until the early 19th century, the average ocean pH was 8.2 but this had fallen to 8.1 by 2015. This may seem a minuscule change, but the mean values disguise the fact that there has been a large fall in the pH of surface waters.

Question 20

Why are coral reefs important?

Answer 20

Coral reefs, an important component of ocean life, stop growing when the pH is less than 7.8.
The situation is now approaching the point that there is a real risk of some marine ecosystems and their goods and services passing the critical threshold of permanent damage. In the case of coral reefs, they are also being threatened by the rise in surface water temperatures. The widespread bleaching of the Great Barrier Reef of Australia is a clear indication that this threat has become a reality.

Question 21

What was the amazon basin drought?

Answer 21

Suffered severe droughts in 2005, 2010, and the drought of 2014 and 2015 was the worst to hit Brazil for 80 years. Amazon holds 17% of the terrestrial carbon store.The trees died and growth rates declined. Forest fires broke out and released CO2.

Question 22

What are the impacts of the Amazon drought?

Answer 22

The Amazon rainforest acts as a giant climate regulator, pumping 20 billion tonnes of water into the atmosphere each day. This is 3 billion tonnes more than the River Amazon discharges into the Atlantic Ocean. The forest’s uniform humidity lowers atmospheric pressure, allowing moisture from the Atlantic to reach almost across the continent. However, since 1990, a cycle of extreme drought and flooding has been observed. Droughts in 2005 and 2010 greatly degraded much of the forest already stressed by prolonged and large-scale deforestation.

In short, the diminishing health of the tropical rainforest means that it is:
declining as a carbon store
sequestering less carbon dioxide from the atmosphere, thereby exacerbating the greenhouse effect
playing a diminished role in the hydrological cycle

Question 23

What is the importance of forests?

Answer 23

It is now widely understood that the impacts of deforestation are global in scale and not just confined to deforested areas. Forests are important for:

• Sequestering carbon dioxide from the atmosphere
• Storing carbon
• Transferring moisture from the soil back into the atmosphere by evapotranspiration

Question 24

how does the Kuznets curve link to the carbon cycle?

Answer 24

It looks as if the environmental Kuznets curve is correct in suggesting that, as they reach higher levels of development and wealth, societies approach a tipping point when the costs of resource exploitation become fully realised and are set against the benefits of resource conservation and protection.

1. UK pre-industrial revolution, remote Amazonia, Indonesia pre 1970s - little income, little environmental degradation.
2. Indonesia today, China in the 20th century - increase in income, a large increase in environmental degradation. Rising income worsens environmental impacts.
3. China today - shallower gradient, almost at peak environmental degradation, middle-level income
4. UK today - (post-industrial service economy), rising income reduces environmental impact

Question 25

What does rising temperatures lead to?

Answer 25

The rising temperatures resulting from GHG emissions are increasing both evaporation rates and the amount of water vapour. This, in turn, is impacting on:

• Precipitation patterns
• River regimes
• Drainage basin stores
• The cryosphere

Question 26

How does the Arctic play a role in global climate?

Answer 26

The Arctic plays an important role in global climate, as its sea ice regulates evaporation and precipitation. What has happened here over the last few decades serves as a warning to the rest of the planet:

• temperatures have risen twice as fast as the global average
• there has been a considerable loss of sea ice; the North-west Passage is now open to summer navigation
• much melting of the permafrost
• carbon uptake by terrestrial plants is increasing because of a lengthening growing season
• a loss of albedo as the ice that once covered the land surface gives way to tundra, and tundra gives way to the taiga. Sunlight that was previously reflected back into space by the white surface is now being increasingly absorbed by the ever darkening land surface. In other words, it is encouraging further climate warming.

Question 27

What have the impacts of climate change been on human health?

Answer 27

In terms of human wellbeing, there has been both positives and negatives. The warming climate is opening up previously ice-bound wilderness areas to tourism. the exploitation of mineral resources, particularly Arctic oil and as, is becoming more feasible. However, climate warming is disrupting and perhaps annihilating traditional ways of life, for example the the fishing and hunting of Inuits in North America and the Sami reindeer herders of northern Eurasia.

Although scientific understanding of the enhanced greenhouse effect is increasing, there is still much uncertainty. As a consequence, there is a commensurate degree of caution when it comes to making global projections.

Question 28

How does the decline in ocean health pose a threat to human health?

Answer 28

The decline in ocean health caused by acidification and bleaching is resulting in changes to marine food webs. In particular, fish and crustacean stocks are both declining and changing their distributions. Such changes are being particularly felt by developing countries.

• The FAO estimates that fishing supports 500 million people, 90% of whom live in developing countries
• Millions of fishing families depend on seafood for income as well as food.
• Seafood is also the dietary preference of some wealthier countries, notably Iceland and Japan.
• Aquaculture is on the rise, but its productivity is also being affected by declining pH values and rising temperatures.

Question 29

How is tourism under threat from climate change?

Answer 29

Tourism is another activity under threat, particularly in those countries, for example in the Caribbean, where coral reefs, now showing signs of degradation, have traditionally attracted scuba-diving tourists. The rising sea level is yet another consequence of climate change that threatens the very survival of tourism and its coastal infrastructure, as for example the Maldives and Seychelles. The costs of strengthening coastal defences can often exceed the financial resources of poorer coastal countries. The Maldives Government had to ask the Japanese Government to give them $60 million to build the 3m high sea wall that protects Malé, the capital city. The tourism sector has the largest percentage share of 21.4% for 2021.

Question 30

What are the natural factors causing uncertainty?

Answer 30

Role of carbon sinks: if greenhouse gas emissions stopped, it would still take a long time for natural systems to restore pre-industrialisation levels.

• About 20% of CO2 remains in the atmosphere for hundreds of years.
• Oceans will reach saturation point, and won’t absorb any more CO2 from the atmosphere.
• Methane storage would take about 100 years to return to normal.

Question 31

What are the human factors causing uncertainty?

Answer 31

Economic growth: more developing countries have emerged economically in the last 30 years, so use more energy and higher emissions e.g. China. There are still many countries to develop and so global emissions may continue to increase. Economic recessions, however, do reduce emissions

Population: more people with high levels of wealth use more energy and cause more missions, especially when the lifestyle uses more machinery and electricity. Education makes people more aware of the issues.

Energy sources: Conferences such as Paris 2016 on emissions reductions have made countries review their energy mixes. Renewable technologies are things that are used more, but also unconventional fossil fuel resources are being exploited.

Question 32

What are tipping points?

Answer 32

The tipping point is a sudden large-scale change within a few decades probably asked for. In 2014 the IPCC identified seven possible tipping points including:

• Long-term droughts
• Collapse of the monsoon climate system
• Arctic Ocean becoming ice-free.

Slower changes may also take place, such as the collapse of the Greenland ice sheet.

Question 33

What are the different feedback mechanisms for different climates?

Answer 33

Carbon from peatlands and permafrost: boreal and tundra biome and climate areas will shift northward as the temperatures increase. Peatlands and permafrost within these will release methane with drying or melting, which traps more heat, causing further drying/melting. These organic layers are a large carbon store, with faster decomposition in warmer climates that release more CO2 in the atmosphere. Also, carbon is released into rivers.

Forest dieback: tropical rainforest areas could become dry and change to less productive grasslands, so absorb less CO2 from the atmosphere – warming will increase, causing more dieback. Drought stress in the boreal forest, with more diseases, pests and wildfires, could change it to grassland and shrubs.

Thermohaline circulation: more freshwater, changes seawater density, which changes ocean currents. For example, the North Atlantic may cause a Gulfstream not to flow far north. Such circulation changes could change how the oceans and atmosphere transfer heat, causing greater warming and more ice melt.

Question 34

What are the adaptation strategies?

Answer 34

• Water conservation and management
• Resilient agricultural systems
• Land-use planning
• Flood risk management
• Solar radiation management

Question 35

What are the mitigation strategies?

Answer 35

• Renewable switching
• Carbon capture and storages
• Afforestation
• Carbon taxation
• Energy efficiency

Question 36

What is water conservation and management and pros&cons?

Answer 36

Water conservation and management encompasses the policies, strategies and activities made to manage water as a sustainable resource, to protect the water environment, and to meet current and future human demand.

Benefits:
- Fewer resources used, less groundwater abstraction.
- Attitudinal change operates on a long-term basis: use more grey (recycled) water.
Costs and Risks:
- Efficiency and conservation cannot match increased demands for water.
- Changing cultural habits of a large water footprint needs promotion and enforcement by governments, e.g. smart meters.

Question 37

What are resilient agricultural systems and their pros&cons?

Answer 37

Climate-resilient agriculture (CRA) is an approach that includes sustainably using existing natural resources through crop and livestock production systems to achieve long-term higher productivity and farm incomes under climate variabilities.

Benefits:
- Higher-tech, drought-tolerant species help resistance to climate change and increase diseases
- Low-tech measures and better practices generate healthier soils and may help carbon dioxide sequestration and water storage: selective irrigation, mulching, cover crops, crop rotation, reduced ploughing, and agroforestry.
- More ‘indoor’ intensive farming.

Costs and risks:
- More expensive technology, seeds and breeds are unavailable to poor subsistence farmers without the aid
- High energy costs from indoor and intensive farming
- Genetic modification is still debated but frequently used to crease resistant strains, e.g. rice and soya.
- Growing food insecurity in many places adds pressure to find ‘quick fixes.

Question 38

What are land-use planning and pros& cons?

Answer 38

Land use zoning protects vulnerable human activity from risky areas such as the coast or floodplains. Usually, this is done to promote more desirable social and environmental outcomes as well as more efficient use of resources.

Benefits:
- Soft management: land-use zoning, building restrictions in vulnerable flood plains and low-lying coasts.
- Enforcing strict runoff controls and soakaways

Costs:
- Public antipathy.
- Abandoning high-risk areas and land-use resettling is often unfeasible, as in megacities such as Dhaka, Bangladesh or Tokyo-Yokohama.
- A political ‘hot potato.
- Needs strong governance, enforcement and compensation.

Question 39

What is flood risk management and pros& cons?

Answer 39

Mitigating and preparing for flooding disasters, analysing risk, and providing a risk analysis system to mitigate the negative impacts caused by flooding. This involves identifying areas with increased flood risk

Benefits:
- Hard management traditionally used: localised flood defences, river dredging.
- Simple changes can reduce flood risk, e.g. permeable tarmac.
- Reduced deforestation and more afforestation upstream to absorb water and reduce downstream flood risk.

Costs and Risks:
- The debate over funding sources, especially in times of economic austerity.
- Costs may be too high even for developed countries.
- Constant maintenance is needed in hard management, e.g. dredging; lapses of management can increase risk.
- People have to leave their homes.

Question 40

What is solar radiation management and its pros&cons?

Answer 40

Involves reducing the amount of heat energy reaching the Earth’s surface.

Benefits:
- The proposal is to use orbiting satellites to reflect some inward radiation back into space, rather like a giant sunshade.
- It could cool the Earth within months and be relatively cheap compared with mitigation.

Costs and Risks:
- ​Untried and untested.
- Would reduce but not eliminate the worst effects of GHGs: for example, it would not alter acidification.
- Expensive.
- Would need to continue geoengineering for decades or centuries as there would be a rapid adjustment in the climate system if SRM stopped suddenly.

Question 41

What is the overall conclusion on adaptation strategies?

Answer 41

Four of these strategies involve a mix of soft- and hard-engineering actions. Some of those actions are low in technology and upfront costs and so, in theory, are possible options for developing countries. A change in traditional practices and customs is often required here. However, there are also actions requiring high inputs of capital and technology that only developed countries can contemplate. The whole of the solar radiation management strategy clearly falls into this category.

Question 42

What are the long-term solutions to combat global warming?

Answer 42

The long-term solution to the global warming crisis lies in rebalancing the carbon cycle, particularly in reducing the concentration of GHGs in the atmosphere. None of the mitigation strategies is straightforward, except possible afforestation. Successful implementation requires a society to change the way it thinks and acts. Some mitigation has a high technological tariff.

The UK has the Department of Energy and Climate Change (DECC) which is responsible for mitigation policies.

Question 43

What is renewable switching?

Answer 43

• The relationship between the big energy producers and the government dictates the amount of switching from fossil fuels to renewables and nuclear power. Renewables provide intermittent electricity, while fossil fuels provide the continuous power essential for our current infrastructure.
• The Climate Change Levy, designed in 2001 to encourage renewable energy investment and use, was cut in 2015.
• Moving from mostly fossil fuels to using renewables would greatly reduce carbon emissions, especially in electricity generation. Renewable technologies and more widespread in developed an emerging countries but are not always available in developing countries.
• The UK policy is to move to a low-carb in future, it will take a long time for any post to be the main source of primary energy.

Question 44

What is carbon capture and storage?

Answer 44

• Few actual geological CCS projects exist globally, despite their potential. Canada’s Boundary Dam is the only large-scale working scheme.
• In 2015, the UK government cancelled its investment in full-scale projects at the gas- and coal-powered plants in Peterhead in Scotland and Drax in Yorkshire, respectively.
• Power stations in large factories that use fossil fuels can be made to capture and store emissions by laws and regulations. However, suitable geologic sites may not be available and the technology involved may be too expensive for developing countries. It also reduces profit for companies and economic priorities may be put fast.

Question 45

What is afforestation?

Answer 45

• Tree planting in the UK is increasing, helping carbon sequestration. It involves the Forestry Commission, charities such as the National Trust and the Woodland Trust, landowners and local authorities.
• The Big Tree Plant campaign encourages communities to plant 1 million new trees, mostly in urban areas.
• Forests are important carbon stores (0.073 tonnes of carbon a year); planting more forests would increase storage and reduce atmospheric concentrations. However, many countries are deforesting for commercial and substance purposes, especially tropical developing or emerging countries.

Question 46

What is energy efficiency?

Answer 46

• The Green Deal scheme encouraged energy-saving improvements to homes, such as efficient boilers and lighting, and improved insulation. It was scrapped in 2015.
• Energy suppliers must comply with the Energy Company Obligation scheme to deliver energy-efficient measures to households.
• All types of machinery and appliances have become more energy-efficient partly because of government regulations which forced manufacturers to improve efficiency. People can change their lifestyles to use less energy. However, as average global wealth increases more energy is being used, so the biggest savings for these mitigation measures are in developed countries.

Question 47

What is carbon taxation?

Answer 47

• The carbon price floor tax sets the minimum price companies have to pay to emit carbon dioxide. It was unpopular with both industry and environmental groups and had a debatable effect on emissions. In 2015, the policy was ‘frozen’
• Lower road taxes for low-carbon-emitting cars were scrapped in 2015.
• In 2015, oil and gas exploration tax relief was expanded to support fossil fuels, hence the fracking debate.
• Governments come to impose taxes on carbon emissions, reducing the profit of businesses and industries and so encouraging them to change to low-carbon alternatives. People may pay for emissions to taxes on vehicle types, based on how much carbon they emit, which encourages people to purchase eco-friendly cars. The Kyoto protocol and Paris agreement but widespread international action on reduction targets and governments introduce regulations in-laws to bring change within their countries.

Question 48

What are the possible outcomes in 2100?

Answer 48

Business as usual:
- Emissions continue rising at current rates. RCP 8.5.
- Temperature rise: as likely as not to exceed 4°C -> businesses impacted by climate change.
- Sea level rises by half to one metre.
- More acidic oceans.

Some mitigation:
- Emissions rise until 2080, then fall. RCP 6.0.
- Temperature rise: likely to exceed 2°C.
- More heatwaves, changes in rainfall patterns and monsoon systems.
- Carbon dioxide concentrations are three to four times higher than pre-industrial levels.

​Strong mitigation:
​- Emissions stabilise at half today’s levels by 2080. RCP 4.5.
​- Temperature rise: more likely than not to exceed 2°C.
- Arctic summer sea ice has almost gone.

​​’Aggressive mitigation’:
​- Emissions halved by 2080. RCP 2.6.
​- Temperature rise: not likely to exceed 2°C.
- Businesses impacted by the policy change.
- May require ‘negative emissions’ (removing CO2 from the air) before 2100.
- CO2 concentration fell before the end of the century.
- Climate impacts are generally constrained, by not being avoided.
- Reduced risk of ‘tipping points’ and irreversible change​.
- If mitigation, at whatever level, is to have any chance of success, it not only requires concerted actions at a national level but, more critically, it requires effective international agreements. Global warming is a global problem requiring global action.

Question 49

When was the latter point first accepted?

Answer 49

The latter point was first accepted by the Kyoto Protocol in 1997, an international agreement which aimed to cut GHG emissions by 5% by 2012. Since then, the reduction targets have been revised upwards and emissions have been reduced. It remains to be seen whether enough is being done or whether the global mitigation strategy should be made even more aggressive. It has to be said that not every country has been enthusiastic about signing up to the succession of agreements tabled since 1997.

Question 50

What was the aim of the Paris agreement?

Answer 50

(Also Copenhagen meeting 2009; Paris meeting in 2015 (COP21) - agreement in 2016)
The most recent of these, the Paris Agreement of 2016, aims to keep the rise in global temperature to less than 2°C above its pre-industrial level. The Agreement now has 140 national signatures. Among the more reluctant signatories are the three largest producers of GHGs: China, India and the USA (withdrew in 2017)

Question 51

What are the attitudes of threat of global warming?

Answer 51

The attitude of a large proportion of the world’s population to the threat of global warming is one of indifference. TNCs may express concern but are often found wanting when it comes to taking appropriate action. When it comes to government attitudes, those whose contributions to GHG emissions are relatively small are vociferous in drawing attention to those countries that are large contributors.