Climate Change: Science And Policy Flashcards
During what timespan stabilised temperature facilitating the evolution of modern humans?
Pleistocene and Holocene
The science of global warming
Some gases block emissions of heat from earth’s surface.
So heat rebounds and is preventing from escaping back into space.
I.e forming a glass screen above the earth like a greenhouse> greenhouse effect> GHG gases
Do GHG occur naturally
Yes
Without them what would the average temperature of earth surface be?
-19C compared to 15C with them
Link between human activity and emission of GHG gases
Enhanced greenhouse effect (activity increases emissions)
Human activity is influencing climate
5 main GHG
Carbon dioxide
Methane
Chlorofluorocarbons (CFC-11 and CFC-12)
Nitrous oxide
Current concentrations of GHGs compared to pre-industrial concentrations
Current concentrations are considerably higher, especially CFCs as man-made gases
Significance of gases having long atmospheric life
It means even if emissions fall, atmospheric concentrations continue to increase for many years
Global warming potential (GWP)
The relative strength of one unit of each gas in contributing to global warming
What has the highest GWP
CFCs
CFC-11 4500
CFC-12 7100
So worst for global warming per unit wise.
What gas has the largest share of warming effect
CO2-61%
So despite CFCs having biggest GWP, it is not the biggest contributor overall.
Where do the release of these gases come from?
Industrial and agricultural activity
Biggest annual GHG emission by sector 2010
Electric power stations-25.6%
How is CO2 released?
Burning fossil fuels
What country emits the most
Asia 53% of global emissions
However Asia is home to 60% of world’s population
Who has contributed the most to global CO2 emissions (cumulative)
US- 25% of historical emissions
Production based emissions
Emissions that occur domestically and offshore where country has jurisdiction
Consumption based emissions
Emissions from domestic final consumption and those caused by the production of imports. (Account for effects of trade
So who has the most production emissions (territorial based)
China-9.8bn
US-5.3bn
Who has the most consumption emissions (domestic consumption and emissions from import production to account for trade)
China 8.4bn (less than their production emissions)
US 5.7bn (more than their production emissions)
Climate change: uncertainty
Climate change impacts
Heat waves occur more often and longer
Extreme precipitation events more intense and frequent.
Ocean warming and acidify
Global mean sea level rise
Consequences of sea level rising
Problems for low lying areas e.g Netherlands.
Requires construction of large scale sea defences
Consequence of rising temperatures
Serious implications for ecology and architecture
3 main challenges with policy responses to climate change
Time lag between actions and effect on climate (uncertainty)
Technology
Global phenomenon
Other problem with climate change policy (regarding CO2)
No end of pipe technology for CO2
I.e cannot reduce CO2 emissions in the same way we can for other air pollutants
Another problem with policy to climate change
Has to implemented on a global scale, as effect is felt globally. No good if one or 2 reduce.
2 types of policy response
Mitigation-limit magnitude of climate change i.e lower amount of GHG released
Adaptation-reduce vulnerability of social/biological systems i.e Lower risks caused by climate change
Mitigation
Policies that focus on reducing energy use and substituting to cleaner fuels
Examples of mitigating policy
Increase forested areas or preventing deforestation to increase amount of carbon absorbed by trees.
Adaptation and examples
Policies that focus on reducing local/regional vulnerabilities e.g flood defences, urban planning, thermal insulation etc.
Aim in policy design for climate change
Select policies yielding greatest net benefit (benefits-costs)
Challenges in policy design for climate change
Uncertainty
Time scale- often short term
Benefits of climate polices
Mitigation-reduce future damage due to reduction in GHG
Adaptation-reduce future damages to social/biological systems
Policy regret- uncertainty
Uncertainty can lead to regret.
Uncertainty can lead to under-adaptation leading to regret
Policy regret- time scale
Different time scale of costs and benefits of policy.
Costs of climate policy as short term
Benefits of policy are seen long term (remember time lag)
So projects to tackle CC are not likely to be favoured.
How they calculate cost benefit
NPV (net present value)
Note: graph shows present value at different years.
If benefits/costs are received far into future, present value will be lower.
So, overall duel objective of climate policies
Maximise net benefit
Minimise regret (by considering uncertainty and time scale)
