Tentafrågor

Question 1

Explain the difference between a 2°C climate sensitivity and a 2°C climate target!

Answer 1

A 2°C climate sensitivity means that average surface temperature increases with 2°C for a doubling of
the concentration of CO2 in the atmosphere.

A 2°C climate target is a target of not increasing surface
temperature with more than 2°C compared to pre-industrial temperature.

Question 2

Give at least two examples of how to reduce C02 from the atmosphere

Answer 2

• Bioenergy with Carbon capture and storage (BECCS)
• Biochar (charcoal from biomass to increase soil carbon)
• Reforestation/afforestation (only a net sink while forests
  grow, then CO2 neutral)
• Direct air capture (chemically scrubbing CO2 from the air)
• Enhanced weathering (powdered minerals that absorb
  CO2)
• Iron fertilization (to stimulate ocean plankton growth)
• Ocean liming (dump lime in oceans to neutralize acidity)

Question 3

What are feed-in tariffs and how do they work?

Answer 3

Feed-in tariffs provide a long-term contract for the electricity price when renewable power is sold to
the grid. It is a technology-specific support, so every renewable energy source has its own tariff. The cost
of the scheme is distributed among all electricity consumers.

Question 4

What is meant by “carbon leakage”?

Answer 4

Carbon leakage is the situation that may occur if, for reasons of costs related to climate policies, business
were to transfer production to other countries which have laxer constraints on greenhouse gas emissions.

Question 5

Give examples of what technologies are typically “on the margin” for all three main types of marginal electricity, for a system which has access to large
amounts of hydro power.

Answer 5

• Instantaneous margin – hydro because it can react fast and is cheap.
• Annual margin – since hydro is cheap, it is used up on annual bases and the increase will come from
  something that is higher in the merit order, most likely coal
• Structural margin – can be anything depending on available resources and policies

Question 6

Give examples of what technologies are typically “on the margin” for all three main types of marginal electricity, for a system that has large amounts of coal and/or gas power, but very little hydro power).

Answer 6

• Instantaneous margin – hydro will likely not be available, so depending on demand level it will be either
  coal or gas.
• Annual margin – sum of the instantaneous margins so a mix of coal and gas.
• Structural margin – can be anything depending on available resources and policies.

Question 7

What principle determines what is on the instantaneous margin in a thermal system?

Answer 7

Merit order curve + demand + flexibility of the source.

Question 8

Atmospheric concentrations of most CFCs and related gases have peaked or even declined significantly, and the ozone layer is expected to recover around 2050-
2070.
Discuss why the climate change problem is expected to be much more difficult!

Answer 8

 The climate change problem is plagued with much larger uncertainties than the problem of ozone
depletion. (Uncertainty regarding climate sensitivity, impacts from climate change, costs of
emission reduction.)

 Reducing greenhouse gas emissions is not restricted to a specific sector or technology - it involves
the whole economy. In contrast there was an easy technical fix to reduce emissions of ozone
depleting substances.

 Climate change affects mostly future generations. It is harder to take action when the ones paying
for the action are not the ones who would suffer from the damages.

Question 9

What is cap- and trade?

Answer 9

Cap and trade is a common term for a government regulatory program designed to limit, or cap, the total level of emissions of certain chemicals, particularly carbon dioxide, as a result of industrial activity.