NO.PZ2024021801000064
问题如下：
Which of the following statements is most accurate? An emission trading system:选项：
A.sets an explicit price on greenhouse gas emissions. B.mandates similar levels of emissions reductions for all actors. C.creates an economic incentive for emissions reductions to occur at the point of least cost.解释：
C
is correct because "an ETS [emission trading system] is a system
based on the exchange of permits for emission units, where actors who exceed
their emissions limits are required to buy permits from those that have emitted
less. The overall quantity of emissions is fixed, and market mechanisms are
used to set their price. In theory, this creates an economic incentive for
emissions reductions to occur at the point of least cost; rather than mandating
similar levels of reductions for all actors, price discovery helps reward those
that can afford to reduce more."
A
is incorrect because "carbon taxation takes a different approach [compared
to ETS] by directly setting an explicit price on GHG emissions (e.g. per tonne
of CO2)."
B
is incorrect because an ETS "creates an economic incentive for emissions
reductions to occur at the point of least cost; rather than mandating similar
levels of reductions for all actors, price discovery helps reward those that
can afford to reduce more."
C选项选出来没问题，但是后半句话“to occur at the point of least cost”说的是使得碳排放在最低成本的时间点发生，这半句话怎么理解比较好？
