In this article I summarize the background research I did on Climate Change for an upcoming report for the Spanish government.
I will first look at the expected consequences of climate change. I will then dive into some considered policy solutions. I will finish the article with some suggestions for action for organizations and individuals.
What are the main consequences of climate change?
In 2016, human activity over the past century is estimated to have caused warming of between 0.8ºC and 1.2ºC above pre industrial levels (1). This rate is likely to increase as greenhouse gas (GHG) emissions increase.There is also the possibility of significant changes in the warming rate due to non-linearities in the Earth System (2). A great deal of work has been done to understand the current and future effects of climate change. This work involves:
- estimating GHG emissions. The main anthropogenic GHG gases studied include carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O).
- estimating climate sensitivity, ie how much will temperature rise given a doubling of atmospheric GHG concentrations.
- estimating the effects of climate change on the world.
Our current global trajectory is estimated in the median case to include 8000 gigatonnes of CO2 equivalent GHG emissions by 2100 and an increase in mean annual temperature of about 4.1ºC by 2100 (3) — though recent research indicates that temperature increase might be higher than 5ºC (4). Furthemore, climate warming may trigger processes that result in increased natural GHG emissions (positive feedback loops), like permafrost melting and the release of methane from the deep ocean, some of which are not included in current climate models (5).
Climate change has already had global lasting consequences, that will worsen if climate change remains unaddressed (6). Those consequences include:
- A median rise in ocean level of about 1.2m by 2100 as warm water expands and polar caps melt (3)
- An increase in the frequency and severity of extreme weather events like heat waves, droughts, wildfires and floods (6)
- Climate change will affect food security (crop yields), increase the range of vector-borne diseases, cause the extinction of climate-sensitive species and subject us to economic hardship (6)
What are the main climate change mitigation and adaptation strategies?
Addressing climate change involves reducing GHG emissions (mitigation), including by decreasing emission sources and increasing emission sinks (sequestration); preparing for the adverse effects of climate change and taking measures to minimise them (adaptation) and planning how to cope with the unavoidable consequences of climate change (loss and damages).
Many levers have been considered for mitigation. Some of the most commonly considered ones, ordered roughly by efficacy, include:
- Implementing a carbon price on the order of 100$ per CO2-equivalent ton would decrease temperature rise by 20% by 2100 (from +4.1ºC to +3.3ºC) (7)
- Retrofitting buildings and industry to increase energy efficiency by 3% would decrease temperature rise by 12% by 2100 (from +4.1ºC to +3.6ºC)
- Subsidizing renewable and nuclear energy on the order of $5/kWh would decrease temperature rise by 5% by 2100 (from +4.1ºC to +3.9ºC)
- Increasing transport energy efficiency by 3% would decrease temperature rise by 5% by 2100 (from +4.1ºC to +3.9ºC). Note that there is a chance that increased transport efficiency will result in greater demand, and increase net emissions (Jevon’s paradox).
- Removing a global coal production subsidy of $100 per tonne coal equivalent would decrease temperature rise by 7% by 2100 (from +4.1ºC to +3.8ºC). On the flip side, taxing fossil fuel production, especially coal, but to a lesser extent of oil and natural gas, would have a similar effect. (7)
- Reducing deforestation by 10% per year would decrease the temperature rise by 2% by 2100 (from +4.1ºC to +4.0ºC).
- Doubling the land available for reforestation would decrease the temperature rise by 2% by 2100 (from +4.1ºC to +4.0ºC). (8)
More speculative (but arguably necessary) levers for mitigation include:
- Research and deployment of carbon removal technologies, such as bioenergy with carbon capture and storage (BECCS) and enhanced mineral weathering, and biochar
- Subsidies supporting electrification of vehicles and heating — which would need to be complemented with renewable sources of electric energy to effectively reduce emissions
- Research on new fertilizers and precision agriculture
- Research on climate friendly alternatives to current methods of steel production and metal powder coating.
- Research on climate friendly alternatives to energy dense fossil fuels for flight and other energy intensive applications.
- Research of new energy sources, such as fusion and thorium-based fission
The list above is non exhaustive, but should give a good idea of the kind of interventions being considered to address mitigation.
Adaptation and damage and losses
While less quantifiable than mitigation and more localized, adaptation interventions are being actively discussed and developed — see eg the UK’s adaptation plan (9). Some promising adaptation interventions include:
- Better climate modelling and extreme weather alert and response
- Identification of areas at risk of flooding and other environmental events
- Prediction of effects on crop yields, and diversifying crops to better withstand climate change
Planning for loss and damage includes plans for accommodating migration waves caused by equatorial places becoming inhospitable and plans for compensating and rehousing people affected by sea level rise.
Who can take action and what options do they have?
By far, the actors best positioned to tackle climate change issues are at the national government level, to the extent that they have the capacity to create incentives to tackle such issues productively via taxation, regulation, subsidies and public investment.
However, city governments, corporations, research organizations and individuals also have an important role to play (10). Some actions they might take include:
- Subnational governments can enact local policies that pursue mitigation, adaptation and loss and damages strategies along the lines of those outlined in the previous section (eg retrofitting buildings, promoting public transport, enacting energy efficiency regulation for buildings, etc), lead efforts to monitor local GHG emissions, understand local effects of climate change and support local initiatives working on effective climate change intervention
- Corporations can invest in adaptation to make their business shockproof in the context of the impacts of climate change, work towards assessing and mitigating their own emissions and offer philanthropic support to effective climate change interventions
- Research organizations have an important role in communicating clearly about climate change and helping policy makers prioritize the most effective solutions. Beyond that, they can help improve our understanding of the most extreme climate change scenarios involving eg permafrost melting or oceanic methane release feedback loops.
- Individuals can influence the implementation of effective policies via voting and activism, donate to support climate change intervention, consider pursuing high impact careers to tackle climate issues and proactively seek out information on climate change. Individual action is also an important tool, some salient examples include reducing consumption of animal products and reducing air and car travel.
This article is by Jaime Sevilla, research visitor at the Center for the Study of Existential Risks of Cambridge University.
This research was sponsored by the Digital Future Society.
I want to thank Natalie Jones and Luke Kemp for their help me understand climate change from a scientific and policy perspective and providing feedback on my writing.
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2. AR5 Synthesis Report: Climate Change 2014 — IPCC [Internet]. [cited 2020 Jun 24]. Available from: https://www.ipcc.ch/report/ar5/syr/
3. En-ROADS Climate Scenario [Internet]. [cited 2020 Jun 17]. Available from: https://en-roads.climateinteractive.org/scenario.html
4. Palmer T. Short-term tests validate long-term estimates of climate change. Nature. 2020 Jun;582(7811):185–6.
5. Ord T. The Precipice: Existential Risk and the Future of Humanity. Bloomsbury Publishing; 2020. 480 p.
6. Anonymous. Climate change consequences [Internet]. Climate Action — European Commission. 2016 [cited 2020 Jun 17]. Available from: https://ec.europa.eu/clima/change/consequences_en
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8. Levin K. 7 Things to Know About the IPCC’s Special Report on Climate Change and Land [Internet]. World Resources Institute. 2019 [cited 2020 Jun 17]. Available from: https://www.wri.org/blog/2019/08/7-things-know-about-ipcc-special-report-land-and-climate
9. Great Britain, Department for Environment F& RA. The national adaptation programme and the third strategy for climate adaptation reporting. 2018.
10. Lorenz S, Porter JJ, Dessai S. Identifying and tracking key climate adaptation actors in the UK. Reg Environ Change. 2019 Oct 1;19(7):2125–38.