Water And Carbon Case Study

Question 1

The Amazon Rainforest (case study)

Answer 1

Located in South America, the world’s largest tropical rainforest covering 40% of the South American landmass. It has a Hot, very wet climate and the vegetation is very dense. Many groups of indigenous people live in the Amazon rainforest and its home to 1 million plant species, over 500 species of mammals and over 200 species of fish. The Amazon is also home to many endangered species, incl. the Amazon manatee (an aquatic mammal)

• water cycle importance in Amazon: causes the Amazon to be very wet- there is a lot of evaporation over the Atlantic Ocean, and the wet air is blown towards the Amazon. This contributes to the amazons very high rainfall. Warm temperatures mean evaporation is high in the rainforest itself, which increases the amount of precipitation. The rainforest has a dense canopy meaning interception is high and as a result less water flows into rivers than might otherwise be expected, and it does so more slowly. Average rainfall is 3000mm/yr. High humidity levels & unstable weather results in heavy rainfall most days. 75% of this total rainfall is intercepted by trees & then to the ground through stem flow. 25% of all rain evaporates. The Amazon has lost 17% of its primaryrainfripesg in the kast 50 years (80% due to cattle ranching, other reasons incl. loggings, mining & for housing).
• carbon cycle importance in Amazon: the Amazon store a lot of carbon in its vegetation & soil (woods are 50% carbon, so it’s a carbon sink. The increasing Co2 concentration in the atmosphere has lead to increased productivity in the Amazon rainforest because the vegetation is able to access more C02 for photosynthesis and the amount of biomass has been increasing. As a result, the amount of C02 has sequestered. However, it does suggest that even through trees are growing more quickly, they are dying younger. As a result, we may not be able to rely on the Amazon as an effective carbon sink in the future.

Question 2

Human activities in the Amazon affecting the water & carbon cycles

Answer 2

Deforestation-
Effects on water cycle: in deforested areas there is no tree canopy to intercept rainfall, so more water reaches the ground surface. There is more increased runoff with less water being intercepted which could increase the risk of flooding. Deforestation reduces rate of evapotranspiration this means less water vapour reaches the atmosphere, fewer clouds form & rainfall is reduced. This increases risk of drought.

Effects on carbon cycle: with our roots to hold the soil together, heavy rain washed away the nutrient-rich top layer of soil, transferring carbon stored in the soil to the hydrosphere. Deforestation means less leaf litter sk humus is not formed. There are less habitats living here and less of the ground is protected from weather conditions. The soil cannot support much new growth, limiting the amount of carbon absorbed. Trees remove C02 from the atmosphere & store it, so fewer trees means more atmospheric C02 enhancing the greenhouse effect & global warming.

Climate change: can severely impact tropical rainforests and in some areas temperature is increasing & rainfall is decreasing, leading to drought. The Amazon experienced severe droughts in 2005 & 2010. Plants & animals living in tropical rainforests are adapted to moist conditions, so many species die in dry weather. Frequent or long periods of drought could,d lead to extinction of some species. Drought can also lead to forest fires, destroying large areas of rainforest, releasing lots of C02 into the atmosphere. Scientists predict a 4degrees temp rise could kill 85% of the Amazon rainforest. This would result in lots of carbon being released into atmosphere as dead material decomposed, and less C02 being taken from the air by trees for photosynthesis.

Question 3

Responses to limit human impacts on the Amazon

Answer 3

• Selective logging: only some trees are felled, most are left standing. This is less damaging to the forest than felling all the trees in an area. If only a few trees are taken from each area the forest structure is kept, the canopy is still there & the soil isn’t exposed. This means the forest is able to regenerate, so the impact on the carbon & water cycle is small.
• environmental law: laws banning use of wood from forests that are not managed sustainably. Laws banning excessive logging. Laws controlling land use, e.g. Brazilian forest code saying landowners have to keep 50-80% of their land as forest.
• protection: many countries have set up national parks & nature reserves to protect rainforests. Within national parks and nature reserves, damaging activities such as logging can be monitored & prevented. Eg: Jau National Park covers an area of over 5.6 million acres & is a UNESCO site.
• replanting: new trees planted to replace the ones cut down. Peru plans to restore 3.2 million hectares of forest by 2020. Its important the same type of tree are planted that were cut down, so that the variety of trees is kept for the future & the local carbon & water cycles return to their initial state. Eg. Expanse of 15 million hectares -link to existing reserves to create a vast conservation corridor in the Northern Amazon.
• Agroforestry: combination of planted trees with annual crops mainly environmental & social advantages over predominant land uses in Amazon, such as cattle pasture. Provided that the forest is not cut down to make way for agroforestry, trees in agroforestry systems would hold more C02 than vegetation would usually hold.

National & international agreements to mitigate climate change in the Amazon
- Tarapoto process: Began in 1995. Forest policy markers from 8 member countries identified 12 criteria to help manage the forest sustainability at management, national & global level. They invested in research, education & technology transfer. And it included proportion of environmental protection areas as against & permanent production areas.
- Amazon cooperation treaty organisation (ACTO): Aimed at promoting sustainable development of 8 member countries. Reverse loss of forest cover worldwide through sustainable forest management. Incl; protection, restoration, afforestation, reforestation, & increased efforts preventing forest degradation & prevent illegal logging.

Question 4

Kyoto protocol (1997)

Answer 4

• Target set for developed countries to reduce greenhouse gas emissions & established concept of trading carbon emissions between member countries.
• Not all developed countries joined (USA incl.). Some then withdraw & some refused to make it legally enforceable.

Question 5

C0P 21 Paris (2015)

Answer 5

• At the Paris C0P 21 climate conference in December 2015, 195 countries adapted the first legally binding global climate deal, due to be enforced by 2020.
• Aim to limit average global temp, increase to 1.5 degrees c above pre-industrial levels.
• Developed countries will continue to support initiatives in developing countries aimed at reducing emissions.

Question 6

C0P 27 (2022)

Answer 6

• Climate summit in Egypt a historic breakthrough to help vunerable countries deal with losses & damages from impacts of climate change.
• C0P 27 presented a dedicated funding for the issue of intense flooding. The ACWA launched at C0P 27 to enable African city leaders to directly access funding to save water issues & sanitation services & improved waste management.

Question 7

How widespread burning & deforestation can affect the regional water cycle

Answer 7

With less trees, most rainfall will go straight to the floor encouraging surface flows as soils become dry & baked being exposed to the sun, reduced Evapotranspiration means air is less moist, so less cloud cover. High flood risk because of increased surface run off.

Question 8

How climate change has impacted soils & rivers within the Amazon

Answer 8

• Vegetation: reduced rainfall rates & high temps play an important role in killing millions of trees. A 3degree rise would result in 75% forest destroyed mainly through drought.
• Soils: Amazonian solis contain 4-9kg of carbon in the upper 59cm of soil layer compared to the 1km2 contained in soils of pastureland. When forests are cleared & burnt, 30-60% is lost to the atmosphere; unburnt vegetation decays & lost without 10yrs. The soil fungi & bacteria that used to recycle dead vegetation dies off.
• Rivers: changes in rainfall & precipitation in may lead to overall reduction in river discharge lead to flash flooding, destroying freshwater ecosystems & water supply for Amazonian people. Warming waters may kill dependent species, reduce water- dissolved oxygen concentrations which could destroy eggs & larvae, relying in dissolved oxygen for survival.