Environmental Engineering Reference
In-Depth Information
The scientific consensus now suggests that impacts will be worse and are more
certain than was anticipated only a few years ago (Berners-Lee and Clark, 2013).
In July 2013 the Moana Loa Observatory in Hawaii, which has been monitoring
atmospheric CO
2
since 1958, recorded 397.23ppm CO
2
with some daily averages
for the month exceeding 400ppm. The annual average increase now exceeds 2ppm
and many scientists believe near to zero emissions are now needed to stabilize the
climate. Over half the permissible one trillion tonnes of carbon has already been
released into the atmosphere if temperature rise is to be 2°C or less. It is likely that
if present trends continue the one trillion tonne mark will be reached in about twenty
five years. Dr Rajenda Pachauri, Chairman of the IPCC, argues that only a high
carbon price will force power companies and manufacturers to reduce their use of
fossil fuels. 'An extremely effective instrument would be to put a price on carbon.
It is only through the market that you can get a large enough and rapid enough
response' he said announcing the release of AR5 in September 2013 (Bawden, 2013).
There is still a great deal of uncertainty within the field of climate science and
considerable discussion over measurements and models of change. Predictions and
forecasts are always presented in terms of possibilities and probabilities, with
recognition that findings are almost always likely to be provisional. Scientists are
always learning more about the factors influencing atmospheric concentrations of
greenhouse gases (primarily CO
2
and methane), the feedback effects of these gases
on the climate system, the nature and extent of local and regional variations, the
future use of fossil fuels (the major cause of CO
2
emissions), the rate of energy take-
up by the oceans, likely global and regional temperature rise, and the rate of melting
of the ice sheets in Greenland and Antarctica, and their effect on sea levels. Also in
2007, the renowned climate scientist James Hansen and his team, after reviewing
the most recent scientific findings, suggested that summer ice melt in West Antarctica
(and Greenland) was far greater than earlier predicted and had not been included
in the IPCC projections because the panel does 'not well account for the nonlinear
physics of wet ice sheet disintegration, ice streams and eroding ice shelves' (Hansen
et al
., 2007: 1950). Referring to the palaeontologic records, Hansen
et al
.'s Royal
Society paper concludes with an exceptionally bleak scenario:
The imminent peril is initiation of dynamical and thermodynamical processes
on the West Antarctic and Greenland ice sheets that produce a situation out of
humanity's control, such that devastating sea-level rise will inevitably occur.
Climate forcing of this century under BAU [business as usual] would dwarf
natural forcings of the past million years; indeed it would probably exceed climate
forcing of the middle Pliocene, when the planet was not more than 2-3°C
warmer and sea level 10-25m higher. The climate sensitivities we have inferred
from palaeoclimate data ensure that a BAU GHG emission scenario would
produce global warming of several degrees Celsius this century, with amplification
at high latitudes.
(Hansen
et al
., 2007: 1949)
Our knowledge is still limited, but the climate crisis is real and extremely serious.
In 2000, Nobel chemist Paul Crutzen of the Max-Planck Institute in Germany coined
a new term - the 'Anthropocene' - designating an epoch of human influence on the
planet. Global, national and regional policies and actions promoting extensive
