Climate Mitigation Guide
Climate change mitigation must become a higher priority if we are to keep global warming within bounds.

What Is Climate Change Mitigation?

Climate change mitigation is a form of climate action that aims to reduce global warming by lowering the greenhouse gas emissions that cause it. Nothing else compares. We can plant as many trees as we like, or erect as many wind turbines as we like, but unless we cut our emissions, the planet is just going to get hotter and hotter.

So how do we reduce our emissions? Basically by doing three things.

First, we need to stop using fossil fuels that emit greenhouse gases like carbon dioxide, and switch to cleaner renewable energies.

Second, we must safeguard our carbon sinks – the huge reserves of carbon stored in forests, oceans and permafrost soil – to prevent them from releasing their carbon into the air.

Thirdly, in case certain energy-intensive industries are unable to switch to renewables fast enough, we need to develop carbon capture and storage technologies to reduce these industrial emissions in the meantime. And we should not forget that trees still possess the world’s most efficient carbon capture and storage technology.

These three objectives should be at the heart of any mitigation strategy that intends to limit the effects of global warming. As we’ll see, other measures are also useful, but the above three are critical.

The greenhouse gases we need to cut are carbon dioxide (CO2) – by far the biggest culprit – methane (CH4), and nitrous oxide (N2O). These are the main heat-trapping gases that drive the greenhouse effect which raises Earth’s temperature and causes global warming.

Climate Mitigation Versus Adaption: Infographic

What Do UN Scientists Say About Climate Change Mitigation?

The Intergovernmental Panel on Climate Change (IPCC), the leading scientific authority on climate, defines climate change mitigation as “actions that reduce the rate of climate change.” This is accomplished “by limiting or preventing greenhouse gas emissions and by enhancing activities that remove these gases from the atmosphere.”

It states that climate mitigation can be applied across all sectors and activities. These include energy, transport, buildings, industry, waste management, agriculture, forestry, and other forms of land management. 1

Mitigation plans go hand in hand with climate change adaptation strategies, since many actions overlap.

The Need for Climate Justice

Climate change mitigation is a global concern. All nations must step up and do what they can. The richer countries must finance the poorer countries, who in turn must improve their standard of good governance. It’s a matter of climate ethics and hard-nosed realpolitik. Because there are no winners and losers here. Either we all win or we all lose. For more on this complex subject, see: What’s the Root Cause of Climate Change?

What Is The Ultimate Aim Of Climate Mitigation?

The global response to repairing Earth’s climate system is led by the UN Framework Convention on Climate Change (UNFCCC), which is the main United Nations treaty on the climate crisis. According to Article 2 of the Convention, the UNFCCC’s ultimate objective is to “prevent dangerous” anthropogenic interference with the climate system… sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.” 2

How To Lower Our Greenhouse Gas Emissions?

Our mitigation of climate change hinges on our ability to lower our greenhouse gas emissions, mainly of CO2. And the only way to reduce our CO2 emissions is to cut back on our use of fossil fuels (coal, oil and natural gas), and switch to sources of renewable energy like wind, solar, hydropower, biomass, and geothermal energy, that produce low or no emissions.

If judged solely on its greenhouse gas emissions, which are very small, nuclear power looks like a possible alternative to fossil fuels. But decommissioning costs and safety hazards are currently seen as insurmountable.

How Much Do We Need To Reduce Greenhouse Gases?

According to the IPCC’s Special Report on Global Warming of 1.5°C (SR15), in order to limit global warming to 1.5°C and thus avoid the worst consequences, we need to reduce our emissions of greenhouse gases by about 45 percent (relative to 2010 levels) by 2030, reaching “net zero” by 2050. Deep cuts in non-CO2 emissions (methane and nitrous oxide) will also be needed. These targets, or something close to them, represent the critical goals for climate change mitigation as this century unfolds.

Will Climate Change Mitigation Succeed?

Not if we continue with our “business as usual” approach. Back in 2010, signatories to the UNFCCC (1992) agreed that global warming should be kept below 2.0 °C (3.6 °F), relative to pre-industrial levels. 3

The Paris Agreement of 2015 confirmed this, but then inserted the lower temperature target of 1.5 °C which, it said, the “parties will do the best” to achieve.

Unfortunately, as the UN’s 2019 Emissions Gap Report confirms, with global energy consumption and CO2 emissions rising, the world is a long way from limiting warming to below 1.5 or even 2 °C. 4 See: What is the Emissions Gap?

Climate Change Mitigation: Methods & Strategies

Although there are several different ways to protect Earth’s climate system, they all feature the need to phase out fossil fuels, reduce energy consumption, preserve and enhance the world’s carbon sinks, and reduce non-CO2 greenhouse gases like methane (CH4) and nitrous oxide (N2O). Let’s take a brief look at each in turn.

Cut Fossil Fuels

Fossil fuels are still king. In 2000, they accounted for 86 percent of the world’s energy consumption. 5 In 2018, eighteen years later – despite the climate crisis – they still accounted for 85 percent of world energy consumption. 6

In 2018, global energy production increased in all fossil fuel sectors: coal production was up 1.9 percent; petroleum was up 2 percent; natural gas increased by 5.2 percent. 7 As yet there is no sign of a significant decline in demand for or production of any fossil fuel. Demand for natural gas is likely to remain strong, with oil not far behind. In Asia, demand for coal will also be strong, though demand in Europe and America will decline. 7

Not only is more fossil fuel energy being used, but energy consumption is increasing (up 2.3 percent in 2018), and so are CO2 emissions (up 2 percent in 2018). 7

CO2 emissions will also rise in 2019, by a projected 0.6 percent. 8

For the most important climate mitigation objective – the phase-out of fossil fuels – to be so neglected, is truly amazing and depressing. Governments really need to get behind climate action and the introduction of renewable energy before it’s too late.

Hydroelectric dam with gates open.
Hydroelectric dam with gates open. An important renewable energy resource, hydropower contributes significantly to the avoidance of greenhouse gas (GHG) emissions and to the mitigation of global warming. Hydropower projects can also act as reservoirs, a sort of storage buffer against the effects of climate change. Photo: © Lawrence W Stolte

Renewables Must Expand Faster

Consumption of renewable energy increased by 14 percent in 2018, providing 26 percent of the world’s electricity. 6 So the trend in respect of renewables remains positive. Even so, it’s still woefully short of what’s needed. To begin with, electricity accounts for only 20 percent of global energy consumption. 9 As well as this, renewables account for only 11 percent of total global energy. Much depends on its growth in the transport and heating sectors, where fossil fuels are dominant. Current forecasts indicate that in these two sectors, renewable energy is likely to experience only modest growth over the next five years. 10

In the United States, in 2018, electricity was sourced from fossil fuels (63 percent), nuclear energy (19.3 percent), and renewable energy sources (17.1 percent). 11

Bottom line: at current rates, fossil fuels are set to remain the dominant global energy source well after 2050 – the date set by the IPCC for “net-zero” fossil fuel emissions.

Electricity Generation Must Become Cleaner

Electrical power plants account for the highest share of greenhouse gas emissions, so decarbonizing them will have an enormous impact on climate mitigation. But in order to switch from fossil fuels to renewable energy, a number of financial supports need to be put in place.

More Investment Needed

According to estimates from Bloomberg New Energy Finance, a mere $138.2 billion was invested in clean energy during the first half of 2018. By contrast, an annual investment of $2.4 trillion is required to boost take-up of renewables in the power industry to the levels needed to limit warming to 1.5°C. 12

More Advanced Energy Infrastructure Needed

According to the U.S. Environmental Protection Agency, moving to a low-carbon society requires large-scale public and private investment in energy infrastructure, with smart grid systems capable of interfacing with and integrating supplies from renewable sources.

How Much Renewable Energy Should We Be Using?

The IPCC’s Special Report on Global Warming of 1.5°C (2018) lays out certain pathways which the world has to follow in order to avoid the worst impacts of climate change. The IPCC’s middle of the range pathways require renewable sources to supply half to two-thirds of primary energy by 2050. 13 As far as electricity generation is concerned, renewables should supply about 70–85 percent of electricity, with fossil fuels (10 percent), natural gas (8 percent), and coal (no more than 2 percent), making up the rest. What’s more, all fossil fuel usage after 2050 should be offset by carbon capture and storage technologies. 13

Interestingly, most of the 1.5°C pathways foresee an increased role for nuclear power (currently supplying 4 percent of global energy) – in one scenario up to 20 percent by 2050. But in some pathways nuclear power decreases.

Reduce Energy Consumption

The public’s behavior and lifestyle can greatly assist climate change mitigation policies, especially when complementing technological change. 14 A high consumption lifestyle typically leaves a larger carbon footprint. Fortunately, there are at least three significant actions they can take, such as: (a) living car-free – saving 2.4 tonnes of CO2 emissions; (b) avoiding one round-trip transatlantic flight – saving 1.6 tonnes; and eating a plant-based diet – saving 0.8 tonnes. 15

Eat Less Meat

Livestock farming is a major natural source of greenhouse gas emissions, including carbon dioxide and methane. This is why the widespread adoption of a vegetarian or vegan diet could cut food-related greenhouse gas emissions by almost two-thirds by 2050. 16 By introducing new vegetarian-friendly dietary guidelines in 2016, which aim to cut meat consumption in half, China hopes to reduce greenhouse gas emissions by 1 billion tonnes by 2030. 17

Conserve Energy

Energy efficiency is another way of protecting our climate. Homes which incorporate a climate-friendly house design, improved insulation, smart energy controllers and energy efficient lighting can make a huge difference. Developing new habits which involve a lower level of energy consumption will also help.

Switch To Electric Cars

Electrification of cars, buses and trucks is a major climate change mitigation strategy. Indeed, decarbonizing the transport system is impossible without switching to electric vehicles.

According to the Union of Concerned Scientists, building a medium-sized electric vehicle (EV) with an 84-mile range results in about 15 per cent more emissions than building an equivalent gasoline vehicle. For bigger EVs travelling more than 250 miles per charge, the manufacturing emissions can be as much as 68 per cent higher.

But this changes as soon as the cars are driven. Electricity is generally a cleaner energy source than gasoline. Battery electric cars offset their higher manufacturing emissions within 18 months – shorter range models can make up the extra emissions within 6 months – and outperform gasoline cars for the rest of their lives. 18

Energy efficiency alone may not be sufficient to meet the IPCC targets. The use of coal, oil and even natural gas in several sectors, notably domestic heating, will need to be progressively reduced. Meantime, switching from coal to natural gas uses up about 45 per cent less carbon dioxide. 19

There is a huge role in the decarbonization process for governments and local authorities. Only they can help to shape markets through the judicious use of carbon taxes as well as subsidies for renewable fuels, EVs and conservation products and services.

Protect Carbon Sinks

Carbon sinks are natural (or artificial) carbon reservoirs that absorb and store carbon-containing compounds for an indefinite period. The most important carbon sinks are the ocean, forests, especially rainforests, permafrost, coastal or estuarine wetlands (reservoirs of blue carbon), and of course all deposits of coal, oil and gas. Protecting these reservoirs – which in practice means preventing their destruction by humans – is a critical element in any climate change mitigation strategy.

The ocean, for example, absorbs 93 percent of the heat of global warming 20 and around 31 percent of all man-made carbon dioxide emissions, even as CO2 concentrations jump to their highest levels for over 800,000 years. 21 For more, see: Effects of Global warming on Oceans.

Unfortunately, ownership of many of these unique carbon sinks is divided between several nations, necessitating a level of cooperation and collaboration which often conflicts with national interests. The Amazon Rainforest and Arctic permafrost are two such sinks, although the ocean is the one that suffers the most environmental pollution. Ships belonging to hundreds if not thousands of corporations, organizations or states, regularly use the ocean, polluting it as they go, heedless of the damage they are causing to its carbon dioxide storage capacity, or its marine inhabitants.

Forests, however, are much smaller than the ocean. As a result, their ability to absorb and store carbon can be compromised much more quickly. Between 1990 and 2016, deforestation cost the world 502,000 square miles (1.3 million square kilometers) of forest. 22 In 2018, another 8.9 million acres of pristine tropical forest was lost. 23

Image shows the basic aims of carbon capture and storage (CCS): the capture of carbon dioxide emissions before they escape into the atmosphere, and their storage underground. The climate science may be clear, but the practical implementation is costly and so far reduces emissions by less than expected.

Carbon Capture & Storage: A Key Climate Change Mitigation Technology

Nearly all climate mitigation pathways outlined by the IPCC in its Fifth Assessment Report (2014) or in its Special Report on Global Warming of 1.5°C (2018), rely on carbon capture and storage (CCS) to achieve their net-zero emissions target in 2050.

This technology, also known as “carbon, capture utilisation and storage” (CCUS) and “bio-energy with carbon capture and storage” (BECCS) – is a CO2 sequestration strategy designed to siphon off CO2 emissions before they get into the atmosphere. 24

Although the underground “storage” technology needed is well known to the oil and gas industry, the “capture” part is proving more difficult. Even Greenpeace seems to be against it, saying that “the technology is largely unproven and will not be ready in time to save the climate.” 25

Tree Planting

Earth is home to around three trillion trees and they play a major role in sequestering the CO2 we emit. That said, scientists calculate that roughly 15 billion are cut down each year – a significant addition to the amount of carbon dioxide that’s driving up global temperatures. 26 See also: 7 Effects of Climate Change on Plants and Trees

Why not plant trees to help reduce our CO2 emissions? A recent study tries to provide answers to this question by estimating the climate change mitigation potential of planting one billion trees. 27 The study concludes that such tree-planting program could absorb two-thirds of all the emissions from human activities that remain in the atmosphere today. For more, see our article: Tree-Planting: the Answer to Global Warming?

Reduce Methane & Nitrous Oxide Emissions

Lowering the emissions of these non-CO2 greenhouse gases is a priority for any climate change plan, not least because – on a pound for pound basis – methane is 84 times more powerful than CO2 (over a 20-year period), while nitrous oxide is nearly 300 times more powerful (over a 100-year period). Methane accounts for roughly 16 percent of all greenhouse gas emissions, nitrous oxide for about 6 percent.

Most man-made methane emissions are produced by livestock farming (about 30 percent) or fossil fuels (19 percent). 28 Agricultural methane comes from microbial decomposers living inside the digestive systems of cows and sheep. Fossil fuel methane comes from seepage and leaks from the pipeline network and other installations of the natural gas industry, which has a global seepage rate of 2.3 percent. See also: Why are Methane Levels Rising?

Special cattle feed to reduce methane emissions from cows
Infographic illustrating cattle feed made from 3-nitrooxypropanol (3-NOP) by animal nutrition giant DSM, which is estimated to reduce emissions of the greenhouse gas methane from dairy cows by 30 percent. © DSM

There are three possible ways to reduce methane emissions, neither of them easy: (a) reduce demand for beef and dairy foods, or (b) develop an animal feed to neutralize the methane inside the animal’s digestive system, or (c) persuade the natural gas industry to improve its seepage rate.

Two-thirds (67 percent) of global nitrous oxide (N2O) emissions come from agriculture. 29 mostly through the use (or over use) of nitrogen fertilizers. Bacteria living in the soil use this nitrogen to produce nitrous oxide which rises up into the atmosphere. A large proportion of the fertilizer is washed away in groundwater, or via drainage ditches, into streams and rivers, eventually reaching the ocean, although a significant amount of this run-off nitrogen is deposited along the way, to be broken down by bacteria, resulting in more nitrous oxide emissions.

There are two possible solutions to this problem: either (a) use less fertilizer or (b) develop alternative fertilizers with less nitrogen. Unfortunately, the agrochemical lobby is extremely powerful and not easily regulated. For more, see: Why is Soil So Important to the Planet?

Climate Change Mitigation Performance Index
The climate change mitigation performance Index assesses countries according to greenhouse gas emissions (50% of score), renewable energy (20%), energy use (20%) and climate policy (20%). Image Credit: Efbrazil (CC BY-SA 4.0)

Climate Change Mitigation Needs International Cooperation

As the IPCC continues to emphasize, climate mitigation is a global issue which requires a global response and a genuinely collaborative effort. Unfortunately, if COP25 (Madrid Dec 2019) is anything to go by, this sort of cooperation is light years away.

In January 2019, the “One Earth Climate Model” was presented at the World Economic Forum in Davos. Involving two years research by scientists at the German Aerospace Center, the University of Technology Sydney (UTS), and the University of Melbourne, it provides a pathway for staying below a 1.5°C temperature rise, by transitioning to 100 percent renewable energy and implementing natural climate protection strategies, such as conservation and reforestation. The cost? A mere $1.7 trillion per year – a bargain compared to other multi-trillion offers. 30

A second new report comes from research group New Climate Institute, creators of Climate Action Tracker. This outlines 17 climate mitigation initiatives involving regions, cities, businesses, and other sub-national bodies. The report states that these projects have the capacity to reduce global GHG emissions in 2030 by 18-21 billion tons of CO2e, thus achieving the goal of 2°C of warming. 31

References

  1. Intergovernmental Panel on Climate Change – Working Group III – “Climate Change Mitigation.” IPCC Fourth Assessment Report 2007. https://www.ipcc.ch/site/assets/uploads/2018/03/ar4-wg2-intro.pdf (1) []
  2. Article 2. United Nations Framework Convention on Climate Change (UNFCCC) (1992). (2) []
  3. UNFCCC. Conference of the Parties (COP) (15 March 2011), Report of the Conference of the Parties on its sixteenth session, held in Cancun from 29 November to 10 December 2010. Addendum. Part two: Action taken by the Conference of the Parties at its sixteenth session (PDF), Geneva, Switzerland: United Nations, p. 3, paragraph 4. (3) []
  4. Emissions Gap Report 2019.” Executive Summary. UNEP. (4) []
  5. International Energy Agency (IEA) 2001. (5) []
  6. B.P. Statistical Review of World Energy 2019. (6) [][]
  7. Global Energy Statistical Yearbook (2019) Enerdata (7) [][][]
  8. Global Carbon Project 2019. (8) []
  9. IEA Global Energy & CO2 Status Report 2019. (9) []
  10. Renewables 2018. International Energy Agency (IEA) (10) []
  11. U.S. Energy Information Administration 2019 (11) []
  12. International Energy Agency. IEA. (12) []
  13. IPCC – Special Report on Global Warming of 1.5°C (SR15) Summary for policymakers. [][]
  14. Edenhofer, Ottmar; Pichs-Madruga, Ramon; et al. (2014). “Summary for Policymakers” (PDF). In IPCC (ed.). Climate change 2014: mitigation of climate change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. (14) []
  15. The climate mitigation gap: education and government recommendations miss the most effective individual actions”. Wynes, Seth; Nicholas, Kimberly A (12 July 2017). Environmental Research Letters. 12 (7): 074024. (15) []
  16. “Eat less meat to avoid dangerous global warming, scientists say.” Fiona Harvey. The Guardian. 21 March 2016. (16) []
  17. “China’s plan to cut meat consumption by 50% cheered by climate campaigners”. Oliver Milman. The Guardian. (20 June 2016). (17) []
  18. Cleaner Cars from Cradle to Grave: How Electric Cars Beat Gasoline Cars on Lifetime Global Warming Emissions.” Union of Concerned Scientists. Oct 29, 2015. – see also: (PDF) https://www.ucsusa.org/sites/default/files/attach/2015/11/Cleaner-Cars-from-Cradle-to-Grave-full-report.pdf (18) []
  19. Natural Gas and the Environment. Naturalgas.org (19) []
  20. 2018 Continues Record Global Ocean Warming.” Lijing Cheng, Jiang Zhu, John Abraham, Kevin E. Trenberth, John T. Fasullo, Bin Zhang, Fujiang Yu, Liying Wan, Xingrong Chen, Xiangzhou Song. Advances in Atmospheric Sciences, March 2019, Volume 36, Issue 3, pp 249–252. First published online 15 Jan, 2019. (20) []
  21. The oceanic sink for anthropogenic CO2 from 1994 to 2007.” Nicolas Gruber, Dominic Clement, Brendan R. Carter, Richard A. Feely, Steven van Heuven, Mario Hoppema, Masao Ishii, Robert M. Key, Alex Kozyr, Siv K. Lauvset, Claire Lo Monaco, Jeremy T. Mathis, Akihiko Murata, Are Olsen, Fiz F. Perez, Christopher L. Sabine, Toste Tanhua, Rik Wanninkhof. Science Vol. 363, Issue 6432, pp. 1193-1199. 15 Mar 2019. (21) []
  22. World Bank survey. (22) []
  23. U.N. Global Assessment Report. Summary for Policymakers. May 2019. Of the 39 billion tonnes of CO2 that we emit into the air each year, roughly 25 percent is removed by forests. (23) []
  24. “Energy in the 21st Century.” John R. Fanchi, Christopher J. Fanchi. (2016). World Scientific Publishing Co Inc. p. 350. (24) []
  25. “False Hope: Why carbon capture and storage won’t save the climate Archived.” Rochon, Emily et al. 2009-05-04. (25) []
  26. “Global count reaches 3 trillion trees.” Rachel Ehrenberg, Nature. September 2, 2015. (26) []
  27. (1) “The global tree restoration potential,” Jean-Francois Bastin, Yelena Finegold, Claude Garcia, Danilo Mollicone, Marcelo Rezende, Devin Routh, Constantin M. Zohner, Thomas W. Crowther. Science 05 Jul 2019: Vol. 365, Issue 6448, pp. 76-79. (2) See also: “Comment on “The global tree restoration potential,” Science (2019). Joseph W. Veldman et al. (3) See also: “Reforesting is a good idea, but it is necessary to know where and how.” (4) “Examining the Viability of Planting Trees to Help Climate Change Mitigation.” NASA. (27) []
  28. Global Methane Budget 2016. Global Carbon Project. (28) []
  29. IPCC – Fourth Assessment Report (2007) (30) []
  30. (31) “DiCaprio-Funded Study: Staying Below 1.5ºC is Totally Possible.” Lorraine Chow. EcoWatch. Jan. 21, 2019. []
  31. “Global climate action from cities, regions and businesses – 2019.” New Climate Institute. (32) []
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