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Human interventions in the carbon cycle

Consequences of changes to the carbon cycle for life on earth
Enhanced climate change is already happening and is set to get worse.  The consequences for people could be very significant.  In the latest report from the Intergovernmental Panel on Climate Change released in 2018 major issues for people globally are discussed.  The report has taken over two years to produce and included the assessment of more than 6,000 scientific studies.  The report was commissioned after the Paris Agreement of 2015 and looked at 2 major scenarios, warming of 1.5°C and warming of 2°C.
The main conclusions are;
We will not achieve the limits we set to global warming agreed in Paris.  We are on track to reach 1.5°C between 2030 and 2052 if temperatures continues to increase at the current rate, and 3°C by the end of the century.
At 2°C warming, major changes take place;
1. There will be almost no coral reefs remaining
2. The Arctic will be completely devoid of ice during summer at least once a decade
3. Huge numbers of animals and plants will become extinct as their habitat becomes smaller.
4. Vulnerable areas such as the low-lying coastal regions of Bangladesh and Vietnam, and island territories like Kiribati and the Maldives will see sea level rise. This will drive millions from their homes
5. There will be more human health risks such as malaria
6. Crop yields will fall dramatically in sub-Saharan Africa, Southeast Asia, and Central and South America. 1
We have already seen more extreme weather over past decades and 2018 was a particularly hazardous year with major big freezes, forest fires, floods and droughts. 2 Christian Aid issued a report that identified ten events that cost more than $1bn each, with four costing more than $7bn each. 3

Consequences climate change

By Enescot - Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=35955459

To meet these challenges of climate change we need mitigation and adaptation.

Human interventions in the carbon cycle designed to influence carbon transfers and mitigate the impacts of climate change.

Mitigation

Mitigation refers to efforts to cut or prevent the emission of greenhouse gases – this would limit the magnitude of future warming. Mitigation can also include new attempts to actually remove carbon currently in the atmosphere.

Climate change adaptation is different, this is how people can manage unavoidable impacts of climate change.

Mitigation involves;
1. Using new technologies
2. Using clean energy sources
3. Changing people's behaviour
4. Making older technology more energy efficient

Climate_Changes_Mitigation

Carbon Capture and Storage (CCS)
Carbon Capture and Storage (CCS) is a technology that can capture up to 90% of the carbon dioxide (CO2) emissions produced in electricity generation and industrial processes from the use of fossil fuels. This prevents the carbon dioxide from entering the atmosphere.

CCS involves;

1. Capture technologies allow the separation of carbon dioxide from gases produced in electricity generation and industrial processes by one of three methods: pre-combustion capture, post-combustion capture and oxyfuel combustion.
2. Transport the CO2 by pipeline or by ship for safe storage. Millions of tonnes of carbon dioxide are already transported annually for commercial purposes by road tanker, ship and pipelines
3. The carbon dioxide is then stored in carefully selected geological rock formation that are typically located several kilometres below the earth's surface. 4

Geological sequestration
New technologies are emerging to fix carbon deep under the ground in a process known as Geologic sequestration. In Iceland a new process is taking place to fix carbon in the abundant Basalt rocks there.  It starts with the capture of waste CO2 from the steam used in the geothermal power plant there, which is then dissolved into large volumes of water. The fizzy liquid is then piped to the injection site 2km away. Then it is pumped 1,000m beneath the surface.  Here, chemical reactions will solidify the CO2 into rock in a matter of months - thus preventing it from escaping back into the atmosphere for millions of years. The carbon forms calcites within the pores of the basalt rock. 5

Other schemes involve actually removing carbon currently in the atmosphere, using Carbon dioxide removal (CDR) technologies.  These include bio-energy with carbon capture and storage, biochar, ocean fertilization, enhanced weathering, and direct air capture when combined with storage.

Biological sequestration
Biological sequestration involves the net removal of CO2 from the atmosphere by plants and micro-organisms and its storage in vegetative biomass and in soils.

This offers many potential advantages:

1. could sequester relatively large volumes of carbon at comparatively low cost
2. protecting or improving soils, water resources, habitat, and biodiversity
3. generate rural income
4. promotes more sustainable agriculture and forestry practices
This means new sinks can be created, for example, afforestation in the UK can capture carbon.

International Policy
There is a long history of trying to resolve climate change and human impact upon the carbon and water cycles.  Climate change is a global issue, and so needs global agreements and solutions.  These take place at huge conferences. A history of these is outlined below;

Climate Change conference action

NEXT TOPIC - Tropical rainforest case study

Sources
1 - Ove Hoegh-Guldberg, Daniela Jacob, Michael Taylor, 2018. Special Report: Global Warming of 1.5 ºC - Summary for Policymakers.  Chapter 1 and 3, IPCC.  Accessed 3rd of January 2019 retrieved from https://www.ipcc.ch/sr15/
2 - Damian Carrington, 2018. Extreme global weather is 'the face of climate change' says leading scientist. The Guardian.  Accessed 3rd of January 2019 retrieved from https://www.theguardian.com/environment/2018/jul/27/extreme-global-weather-climate-change-michael-mann

3 – Christian Aid, 2018. Counting The Cost: A Year of Climate Breakdown. Accessed 3rd of January 2019 retrieved from https://mediacentre.christianaid.org.uk/download?id=4170&pn...pdf
4 – Carbon Capture and Storage Association, What is CCS?  http://www.ccsassociation.org/what-is-ccs/
5 - Valeria Perasso, 2018.  Turning carbon dioxide into rock – forever. BBC. Accessed 3rd of January 2019 retrieved from https://www.bbc.co.uk/news/world-43789527
 

Written by Rob Gamesby

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