Lecture 1 - Introduction Flashcards
What is climate change mitigation?
Practical action to reduce emissions of anthropogenic GHGs into the atmosphere in order to prevent global temp increases and the consequent impacts.
Why is cc action such a big challenge?
- Uncertain in form and extent
- Gradual onset rather than directly confrontational
- Long term threat rather than immediate. BUT requires action now.
- Broad in its impacts
- Effective remedies are beyond the scope of any one nation - requires international cooperation on an unprecedented scale.
How can we justify cc mitigation?
Benefits of a certain level of mitigation must outweigh the costs. Benefits are the avoided impacts.
Refer to graph with time on the x axis and utility on the y. Concave line for no mitigation and convex for mitigation. Mitigate where the mitigation like is above the no mitigation line.
How do we measure the benefits of mitigation?
- Type 1: currently measurable market impacts, e.g. impaction GDP.
- Type 2: market impacts not readily measurable, e.g. impact on tourism.
- Type 3: insurance value against high damages - we are naturally risk averse when it comes to events that could cause catastrophic damage. What would we be prepared to pay to avoid a small probability of a highly damaging outcome? E.g. defence - nations pay a large a lot even though risk is low.
- Type 4: non-market impacts, e.g. damage to environmental landmarks such as the Great Barrier Reef
What discount rate should be used?
Factors to consider:
- What if there is no tomorrow? What is the probability of extinction.
- Utility of future generations.
- Marginal elasticity of utility - wealthier people value an extra $ less than poor people. We assume that we will be wealthier in the future, therefore $ worth less to us in the future.
- Ethically it should be zero but typically use a social discount of 3-5%.
What do we need to do to prevent cc?
- Limit negative impacts of cc - prevent dangerous cc.
- Limit rise in global temp increases to less than 2C above pre industrial levels.
- Stabilise concentration of GHGs in the atmosphere to ~450ppm.
- Reduce GHG emissions into the atmosphere - halve by 2050.
Likelihood of limiting temp rise if we keep atmospheric concentration of CO2 to 450ppm by 2100
1.5C - more unlikely than likely
2C - likely
3C - likely
Likelihood of limiting temp rise if we keep atmospheric concentration of CO2 to 500ppm (no overshoot) by 2100
1.5C - unlikely
2C - more likely than not
3C - likely
Likelihood of limiting temp rise if we keep atmospheric concentration of CO2 to 500ppm (overshoot to 530) by 2100
1.5C - unlikely
2C - about as likely as not
3C - likely
How can stabilisation be achieved?
- Multiple pathways
- Trade off between emissions peak vs rate of reduction thereafter.
- Danger of overshooting and the consequences of this.
- Key concept: probability -> how likely is it that a certain pathway will lead to a certain temp rise?
- Cumulative emissions also matter - there is a cumulative CO2 budget and if we exceed it then it’s unlikely that we’ll achieve the 2C.
Carbon budget
If cumulative emissions (2011-2100) are 1000GtCO2 then we have a 66% chance of keeping within 2C (IPCC)
How much of the budget is left?
Cumulative budget 2011-2100: 1000 GtCO2
Already emitted to 2015: 150
Expected deforestation emissions to 2100: 100
Expected process emissions from cement production to 2100: 150
=> Remaining budget = 600
What is the current annual rate of emissions?
How many years before we blow our CO2 budget?
35 GtCO2
Given that we have 600GtCO2 remaining, this gives us 17 years.
What current pathway are we on?
NDCs for 2013 exceed the warming limits in the Paris Agreement,
Who should be responsible for reducing emissions?
- Current largest emitters (total emissions - China, US, EU; per capital - US, Saudi Arabia, Canada)
- Historical emitters (US, EU, China)
- But development and CO2 emissions are still highly interlinked => do countries that are still developing therefore have a right to emit?
- Some of the most affected countries are the lowest emitters
What is climate justice/how can we make mitigation fair?
- The largest share of historical and current global emissions of GHG has originated in developed countries.
- Per capita emissions in developing countries are still relatively low.
- The share of global emissions originating in developing countries will grow to meet their social and developmental needs.
What are the key principles of climate justice?
- Equality - we all have the same right to the common resource of the atmosphere
- Historic responsibility - “polluter pays” principle
- Capacity to pay
What global mitigation strategies have been proposed?
- Carbon budget (equal emissions entitlement) - proportion of emissions allocated on basis of population.
- Index based (historical responsibility) - share of mitigation based on share of historical emissions.
- Contraction and convergence (equal emissions entitlement) - country emissions follow a pathway where they contract to converge on the same emissions per capital by a specified date.
- Common but differentiated convergence (equal emissions entitlement & historical responsibility) - As above but countries further differentiated on their level of economic development. Countries below per capita threshold can carry on BAU.
- Cost proportional to GDP per capita (capacity to pay) - targets based on equal mitigation costs as a % of GDP.
- Income classification approach (capacity to pay) - targets set based on mitigation costs as a % of GDP but higher % for wealthier countries.
Which global mitigation strategy has the most support?
Contraction and convergence (equal emissions entitlement) - country emissions follow a pathway where they contract to converge on the same emissions per capital by a specified date.
As per the UNFCCC, which countries should take the lead in cc mitigation?
Annex 1 countries (developed countries).
Other classification are:
- Non-annex 1 (developing countries) and
- Least developed countries and alliance of small island states.
Where do the bulk of GHG emissions come from?
Industrial processes
Where do GHG emissions come from?
- Primary energy - electricity, transport, heat, industry
- Land use change
- Agriculture
What are the drivers of energy demand (and therefore CO2 emissions)?
CO2 emissions =
Population x income x energy intensity x CO2 intensity
=
Population x (GDP/population) x (energy/GDP) x (CO2/energy)
What can be done to decouple CO2 emissions from growth?
Population x income x energy intensity x CO2 intensity
If we assume that population and income will continue to grow, we need to reduce energy and CO2 intensity:
- increase energy efficiency
- reduce energy demand
- behavioural changes
- switch to less CO2 intensive fuels
- more renewables
- CCS
What does the energy system consist of?
Primary energy sources (e.g. coal, oil. gas, renewables, nuclear) -> energy transformation processes (e.g. electricity, heating, transport) -> energy service (lighting, electrical appliances, heat, transport)
How can we reduce CO2 emissions
- Supply side - switch to cleaner fuels, renewables, nuclear, CCS
- Demand side - reduce demand, increase energy efficiency, change technologies to those that don’t use fossil fuels (e.g. EVs)
What are the main factors to consider for a new technology?
- How much energy can it deliver? Or save?
- How much will it cost? Economic and social.
- What are the risks?
