Environmental Engineering Reference
In-Depth Information
term climate goals and for the investigation of the possible roles of adaptation. The results
should be directly supportive of international policy development aimed at the cooperative
control of global warming through GHG emission reduction.
Nevertheless,sincetheglobaleffortsofmitigationareasyetbarelyevidentintermsof
total global emissions, the existing SRES scenarios are still useful to capture the spectrum
of the currently most plausible global economic development for the twenty-first century.
In addition, you will find (if you read further) that much of the scientific literature prior
to 2013 used the SRES approach. This is why I have explained their development in some
detail.
What do the modelling studies using the SRES scenarios indicate for the future global
climate? There is a very quick, rough and lazy way to answer this question. Essentially, it
is that the climate trends we have been witnessing over the last 50 years will continue -
except they will become more and more pronounced and the rate of change will generally
increase.
By the end of the twenty-first century, the average global temperature will have in-
creased by between 1.8°C (range 1.1 to 2.9) and 4.0°C (range 2.4 to 6.4) since 1995. Re-
member that we have already experienced a 0.6°C increase between the beginning of mod-
ern industrialization and 1995. Therefore, we should really add 0.6°C to these numbers to
appreciate the full picture. The low estimate is for the lowest emission scenario (B1), while
the high estimate comes from the highest emission scenario (A1FI). The A2 scenario is
quite similar to A1FI (3.4°C within a range of 2.0 to 5.4). These latter two scenarios sadly
come closest to describing the emerging economic world for at least the next 25 years, as
shown by the most recent global CO
2
emission data we examined in the climate chapter. In
the absence of action to aggressively reduce our GHG emissions (not just a reduction of the
carbon intensity of various elements of national economies), global warming will contin-
ue for centuries beyond the year 2100. Unfortunately, very few governments appear to be
prepared for the necessary action. Regardless as to how we look at it, by the year 2100, we
can expect that our children and grandchildren will be living in a world that has an average
global temperature somewhere between 2°C and 7°C warmer than that known by our par-
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