10.1.2.4 Uncertainty Is Pervasive
There are many uncertainties regarding the magnitude of future climate change,
its consequences and the costs, benefits and implementation barriers of possible
solutions. Future emissions to the atmosphere are inherently uncertain and can
only be explored on the basis of scenarios. The change in concentration of GHGs
that would result from a given emission rate is much less uncertain. But the
timing, extent, and distribution of climate change and sea level rise for a
given concentration of GHGs is not well known due to limitations in modelling
climate change at the regional level. The impacts of climate change on ecosystems
and humanity is known with limited certainty. The potential for an unspecified,
low-probability, but catastrophic turn of events haunts the problem.
While uncertainties are great, they are not distributed evenly throughout the
problem. The cost implications of emissions mitigation are better known than
the more distant (in time) potential benefits from mitigation. In part this
is because of temporal proximity, but it is also because most of the costs associated
with emissions mitigation pass through markets, whereas many of the benefits
do not. Some uncertainties will remain unresolved regardless of the decisions
made. This follows directly from the fact that there is only one observed history.
All the other potential histories are counterfactual, and therefore constructs
from analytical tools that are limited in their veracity. In decision making
terms the problem of climate change mitigation requires decision making under
uncertainty. Given the long lead times of mitigation action, fully resolving
uncertainties would make an adequate response infeasible.
10.1.2.5 The Consequences Are Potentially Irreversible
Many global biogeochemical processes have long time scales. Sea level changes
as a consequence of changes in mean global temperature can take more than 1000
years to play out. Similarly, changes in the concentration of GHGs can rise
rapidly, but decline slowly. And, even if concentrations can be reduced, the
nature of the climate system is such that it might not return to the same climatic
state associated with an earlier concentration.
10.1.2.6 The Global Institutions Needed to Address the
Issue Are only Partially Formed
The UNFCCC has been ratified by more than 170 parties and entered into force
in 1994. It provides the institutional foundations upon which international
climate change negotiations occur. It sets as its ultimate objective the stabilization
of the concentration of GHGs in the atmosphere at levels that prevent dangerous
anthropogenic interferences with the climate. However, the UNFCCC establishes
a process and does not create the institutions for implementing the objective.
The objective has not yet been quantified. The term dangerous is
left open to interpretation by the parties.
The Kyoto Protocol of December 1997, described in Chapter
1, represents a further important step in the international regime formation
under the UNFCCC. The Kyoto Protocol has brought a number of new elements and
broadened the context of the decision-making process regarding implementation
of climate change policy. Ultimately, further institutional development is needed
for the UNFCCC to meet its final objective.