|Table TS.7: Balancing the near-term mitigation
|Favouring modest early abatement
|Favouring stringent early abatement
- Energy technologies are changing and improved versions of existing
technologies are becoming available, even without policy intervention.
- Modest early deployment of rapidly improving technologies allows learning-curve
cost reductions, without premature lock-in to existing, low-productivity
- The development of radically advanced technologies will require investment
in basic research.
- Availability of low-cost measures may have substantial
impact on emissions trajectories.
- Endogenous (market-induced) change could accelerate development of
low-cost solutions (learning-by-doing).
- Clustering effects highlight the importance of moving to
lower emission trajectories.
- Induces early switch of corporate energy R&D from
fossil frontier developments to low carbon technologies.
|Capital stock and inertia
- Beginning with initially modest emissions limits avoids premature
retirement of existing capital stocks and takes advantage of the natural
rate of capital stock turnover.
- It also reduces the switching cost of existing capital and prevents
rising prices of investments caused by crowding out effects.
- Exploit more fully natural stock turnover by influencing
new investments from the present onwards.
- By limiting emissions to levels consistent with low CO2
concentrations, preserves an option to limit CO2 concentrations
to low levels using current technology.
- Reduces the risks from uncertainties in stabilization
constraints and hence the risk of being forced into very
rapid reductions that would require premature capital
|Social effects and inertia
- Gradual emission reduction reduces the extent of induced sectoral
unemployment by giving more time to retrain the workforce and for structural
shifts in the labour market and education.
- Reduces welfare losses associated with the need for fast changes in
peoples lifestyles and living arrangements.
- Especially if lower stabilization targets would be
required ultimately, stronger early action reduces the
maximum rate of emissions abatement required
subsequently and reduces associated transitional
problems, disruption, and the welfare losses associated with the need
for faster later changes in peoples lifestyles and living arrangements.
|Discounting and intergenerational equity
- Reduces the present value of future abatement costs (ceteris paribus),
but possibly reduces future relative costs by furnishing cheap technologies
and increasing future income levels.
- Reduces impacts and (ceteris paribus) reduces their
|Carbon cycle and radiative change
- Small increase in near-term, transient CO2 concentration.
- More early emissions absorbed, thus enabling higher total carbon emissions
this century under a given stabilization constraint (to be compensated
by lower emissions thereafter).
- Small decrease in near-term, transient CO2
- Reduces peak rates in temperature change.
|Climate change impacts
- Little evidence on damages from multi-decade episodes of relatively
rapid change in the past.
- Avoids possibly higher damages caused by faster rates
of climate change.