Mitigation strategies to cut global emissions of GHG

Energy efficiency and conservation

• UK - domestic demands account for 1/3rd of primary energy consumption and service based activities account for 16%

• this can be done by generating electricity from solar power and heat exchanges, and conserving energy with effective insulation, south facing windows to maximise solar gain

• advantages - a family having solar panels installed will save £1000 in total, gov. has committed to spend over £9.7 billion on decarbonising buildings, does not require

• disadvantages - needs investment in infrastructure which is paid for more by firms/people, cost of expanding this VAT relief for materials is estimated £50 million and rising to £65 million in 2026-7

Fuel shifts and low-carbon sources

• energy use fell by 6.6% in 2014, despite economic growth of nearly 3%

• by 2014, coal consumption had fallen to levels not seen since the 19th century

• under the directive the UK has to achieve 15% target for electricity generation from renewables by 2020

• advantages - FF prices are rising so renewables are a strategic long term investment

• disadvantages - UK still relies on FF for 86% of its energy supply and lags behind other EU countries, requires sig. investment , amount of energy produced by solar and wind fluctuates depending on the weather

Carbon capture and storage

• CO2 is separated from power station emissions, then compressed and transported by pipeline to storage areas, then it is injected into porous rock deep underground where it is stored permanently (transferred to long-term storage)

• advantages - has the potential to reduce CO2 emissions from coal and gas fired power stations by 80-90%, large polluting firms on board as they are able to continue their high emission activities

• disadvantages - the Drax project in North Yorkshire (designed to capture 2mill tonnes of CO2/yr) was axed in 2016 due to rising costs, it uses large amounts of energy - 20% of a power plants output needed, requires storage reservoirs with specific geological conditions i.e. porous rock overlain by impermeable strata

Forestry strategies

• deforestation responsible for around 1/5th of global emissions

• UK gov. pledged £50 mill to the planting of 11 mill trees by 2022

• UNREDD and ARPA

• advantages - stabilises regional water cycle, offset 430 mill tonnes of CO2/yr, prevents flood risk, boosts biodiversity, promotes ecotourism, cheap strategy that can be rolled out in all locations

• disadvantages - land which is forested is expensive

Geoengineering - Ocean fertilisation (GHG removal)

• nutrients e.g. iron artificially added to oceans, enhancing photosynthesis via phytoplankton and removing CO2 from the atmosphere

• 50% of photosynthesis occurs in the oceans

• puts carbon back to the long-term store of carbon via the biological pump

• Disadvantages:

  • drawing down CO2 and sequestering carbon in the deep sea are only of the possible consequences, iron seeding can stimulate growth of some algae species that give rise to red tides + other toxic acids in the oceans

  • can disrupt natural food chain and cause competition for oxygen in oceans

  • $75 per ton of carbon which is expensive

  • would also need international cooperation - who would fund?

Geoengineering - enhanced weathering (GHG removal)

• crushed silicate minerals e.g. olivine are spread on large areas of agricultural land where plant roots and microbes in the soil speed up the chemical reactions

• olivine react on exposure to air and absorb CO2 to form carbonates

• carbonates then discharge via rivers into oceans and become part of the inorganic biological pump

• Advantages - 1. when used over nearly 1/3rd of earths tropical land could reduce atm. CO2 conc. by between 30ppm and 300ppm by 2100, 2. scalable, 3. reducing ocean acidification

• Disadvantages - 1. cost and practicality major drawback from implementing large scale, 2. cost in total of $600 trillion, 3. needs further research, 4. large amounts of heavy rock must be collected

Solar radiation management - stratospheric aerosol injection

• uses tiny reflective sulphate particles/aerosols to reflect sunlight into space to cool planet and reverse global warming - inspired by volcanoes

• spraying these particles into the atm. with planes, balloons

• method is feasible with existing tech., can be implemented in a short period of time at relatively low cost

• 5 mill tonnes of albedo-enhancing aerosol to alt. of 20-30km estimated to cost $2 billion - but annual costs for climate damage or mitigation range from $200 bill to 2 trill

• loss of crops and access to fresh water due to reduced rainfall could lead to starvation and suffering

• consequences on ecological system are unknown and potentially vary with differing impacts on marine vs. terrestrial biomes

geoengineering - concluding thoughts

• some geoengineering strategies will have a global impact - public acceptance might be hard to achieve, especially on a global scale

• some methods are unclear on how it would be policed

• who would implement? countries? companies? - uncertainties and ethical questions

• environmental impacts seem widespread - more research and models needed

• costs - some cost more than others

• is acceptance an economic thing? political? social? environ.?

• however, do we have the luxury of not doing this?

Mitigation is needed on all scales to be effective

• individual - lifestyle and consumption choices e.g. recycling more, avoiding fast fashion

• local - local gov. strategies on planning, recycling, transport

• national - gov. policies e.g. UK CC Act 2008, and national tax frameworks, national campaign groups e.g. Extinction Reb.

• Global - international agreements e.g. Kyoto, COP21 Paris, global business, global markets for carbon trading

Why is mitigation needed?

• the IPCC warned in 2014 that it was technically possible to keep within target of 2C increase in avg. global temp. but that FF use needed sig. reductions and total elimination by 2100

• scientists believe that threshold might be reached resulting in damaging and irreversible consequences for climate and other global environment systems

• mitigation strategies ensure the problems in the future do not spiral beyond the means of the adaptation strategies

• goal of mitiation:

  • “stabilize GHG levels in a timeframe sufficient to allow ecosystems to adapt naturally to CC, ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner” -IPCC 2014

Role of UN and their mitigation strategies

• UNFCCC conference of parties - annual meeting to agree to targets e.g. Paris 2015

• this requires global scale agreement and national actions, both of which have proved to be problematic

• long history of global attempts to limit carbon emissions, starting with Rio COP in 1992

• Kyoto was the first major attempt to implement a treaty

• the outcomes of COP treaties have not achieved the high expectations they aspired, some countries have found it easier to make cuts to carbon emissions than others

• since 1992, GHG emissions have rise by 50%

Evaluation of mitigation - needing adaptation as well

• further planetary warming is inevitable even if mitigation is successful (RCP 2.5) due to the scale of the issue

• time-lag between emissions and warming and it will take considerable time at the global scale to bring carbon emissions under control

• if mitigation strategies drastically reduce future emissions of GHG, past emissions will continue to have an effect in future

• therefore, adaptation strategies are required to manage the situation in the near term

Evaluation of mitigation - controlling CO2 emissions

• controlling CO2 in the atm. should be the biggest priority as 7% of the enhanced GHG effect is due to CO2

• most CO2 emissions come from burning FF, so energy should be the main priority on the mitigation agenda

• if CO2 levels could be limited to 450 ppm, it would be likely to contain the rise in temp. to less than 2C limit

• ideal = decarbonised economy based on power sources that do not use carbon-based fuels or limits their use i.e. de-coupling economic growth from carbon emissions

Why are both mitigation and adaptation strategies needed

• when both strategies are taken together, they can sig. reduce risks - mitigation is necessary to reduce the rate and magnitude of CC, while adaptation is essential to reduce the damages from CC that cannot be avoided

• CC is being experienced in all parts of the world, however, some parts are facing extreme risks from CC now and in a more intense way in the future

• therefore, a global effort to mitigate against global CC is required yet adaptation strategies are more localised in focus

• while CC is a global issue, it is experienced at a local scale

Why are mitigation and adaptation complementary strategies

• emissions reductions over the next few decades can reduce climate risks in the 21st century and beyond

• this improves prospects for effective adaptation

• this also reduces costs of mitigation in the longer term

• this contributes to climate-resilient pathways for sustainable development

Kondratieff wave - green technology