28
3.1 Introduction
Anyone who says there is not a dramatic change in weather patterns,
I think is denying reality.
New York Governor Andrew Cuomo (Resnikoff, 2012).
Climate change is one of the greatest ecological, social and economic challenges facing society today
(CSIRO, 2011) (Fig. 3.1). The Intergovernmental Panel on Climate Change (IPCC) concluded in their
Fourth Assessment Report (2007) that there was unequivocal evidence of warming of the global climate system (IPCC, 2007a). This statement has been further supported and confirmed in the latest
report from the IPCC, Climate Change 2013: The Physical Science Basis. Contribution of Working
Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, warning
that ‘Observational and model studies of temperature change, climate feedbacks and changes in the
Earth’s energy budget together provide confidence in the magnitude of global warming in response to
past and future forcing’ (IPCC, 2013, p. 16). Climate change is recognised as being indisputable,
whereby plausible scenarios for global change and emissions of greenhouse gases conclude that temperatures would increase by between 2–6 °C (relative to 1980–1999) by the end of the century. The
latest scientific research has concluded that after accounting for thermal expansion of ocean waters
and ice cap retreat, that sea levels would rise from about 0.79 m to more than 1.0 m and even as high
as 1.4 m by 2100 (IPCC, 2007b; IPCC, 2013).
Research findings presented at the Copenhagen Climate Congress in 2009 projected sea level to
rise to 1.9 metres, and in some arguments these projections are considered as being conservative
(DCC, 2009). These conclusions have raised some debate about whether the climate models used are
reliable. Other reactions include support of these models, with some scientists arguing that the IPCC
predictions are too conservative. Despite this debate, the IPCC fifth Assessment Report supports a
scenario that ‘positive climate change feedback’
1
may amplify the effects of climate change and force
a sustained global warming greater than the threshold of 2 °C above pre-industrial times thereby leading to the near- complete loss of the Greenland ice sheet, causing an estimated global mean sea level
rise of about up to 7 metres. The IPCC has offered this statement with a rating of ‘medium confidence’
(IPCC, 2014a, p. 1139).
All these predictions are subject to levels of uncertainty recognizing that the nature of the variables
that influence sea level rise are uncertain and complex. For example, the predictions do not take into
account cascading effects that could more rapidly result in a drastic increase in sea level rise. One
example that could lead to cascading effects is if rapid melting of ice sheets occurs, it could result in
a non-uniform rate of sea level rise due to adjustments in the Earth’s gravitational field (IPCC, 2012).
Another example that could cause cascading effects is the release of trapped methane hydrates gases
under the Arctic sea ice sheets (Ryskin, 2003). In 2012 airborne study findings by NASA measured
surprising high levels of greenhouse gas methane hydrate coming from the cracks in Arctic sea ice
sheets, and partial sea ice cover (NASA, 2012).
Considering these uncertain scenarios, adaptation and approaches to climate change effects needs
to be approached and managed in a flexible manner to avoid unnecessary early or late interventions,
to manage risks from sea level rise and other related impacts.
1 An interaction in which a perturbation in one climate quantity causes a change in a second, and the change in the second quantity ultimately leads to an additional change in the first. A negative feedback is one in which the initial perturbation is weakened by the changes it causes; a positive feedback is one in which the initial perturbation is enhanced. In
the IPCC fifth Assessment Report, Working Group III contribution to the IPCC fifth Assessment Report - Mitigation to
Climate Change Technical Summary Final Draft, a somewhat narrower definition is often used in which the climate
quantity that is perturbed is the global mean surface temperature, which in turn causes changes in the global radiation
budget. In either case, the initial perturbation can either be externally forced or arise as part of internal variability (IPCC,
2014a, p. 1450).
3 The Challenge of a Changing Environment
3.1 Introduction
Anyone who says there is not a dramatic change in weather patterns,
I think is denying reality.
New York Governor Andrew Cuomo (Resnikoff, 2012).
Climate change is one of the greatest ecological, social and economic challenges facing society today
(CSIRO, 2011) (Fig. 3.1). The Intergovernmental Panel on Climate Change (IPCC) concluded in their
Fourth Assessment Report (2007) that there was unequivocal evidence of warming of the global climate system (IPCC, 2007a). This statement has been further supported and confirmed in the latest
report from the IPCC, Climate Change 2013: The Physical Science Basis. Contribution of Working
Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, warning
that ‘Observational and model studies of temperature change, climate feedbacks and changes in the
Earth’s energy budget together provide confidence in the magnitude of global warming in response to
past and future forcing’ (IPCC, 2013, p. 16). Climate change is recognised as being indisputable,
whereby plausible scenarios for global change and emissions of greenhouse gases conclude that temperatures would increase by between 2–6 °C (relative to 1980–1999) by the end of the century. The
latest scientific research has concluded that after accounting for thermal expansion of ocean waters
and ice cap retreat, that sea levels would rise from about 0.79 m to more than 1.0 m and even as high
as 1.4 m by 2100 (IPCC, 2007b; IPCC, 2013).
Research findings presented at the Copenhagen Climate Congress in 2009 projected sea level to
rise to 1.9 metres, and in some arguments these projections are considered as being conservative
(DCC, 2009). These conclusions have raised some debate about whether the climate models used are
reliable. Other reactions include support of these models, with some scientists arguing that the IPCC
predictions are too conservative. Despite this debate, the IPCC fifth Assessment Report supports a
scenario that ‘positive climate change feedback’
1
may amplify the effects of climate change and force
a sustained global warming greater than the threshold of 2 °C above pre-industrial times thereby leading to the near- complete loss of the Greenland ice sheet, causing an estimated global mean sea level
rise of about up to 7 metres. The IPCC has offered this statement with a rating of ‘medium confidence’
(IPCC, 2014a, p. 1139).
All these predictions are subject to levels of uncertainty recognizing that the nature of the variables
that influence sea level rise are uncertain and complex. For example, the predictions do not take into
account cascading effects that could more rapidly result in a drastic increase in sea level rise. One
example that could lead to cascading effects is if rapid melting of ice sheets occurs, it could result in
a non-uniform rate of sea level rise due to adjustments in the Earth’s gravitational field (IPCC, 2012).
Another example that could cause cascading effects is the release of trapped methane hydrates gases
under the Arctic sea ice sheets (Ryskin, 2003). In 2012 airborne study findings by NASA measured
surprising high levels of greenhouse gas methane hydrate coming from the cracks in Arctic sea ice
sheets, and partial sea ice cover (NASA, 2012).
Considering these uncertain scenarios, adaptation and approaches to climate change effects needs
to be approached and managed in a flexible manner to avoid unnecessary early or late interventions,
to manage risks from sea level rise and other related impacts.
1 An interaction in which a perturbation in one climate quantity causes a change in a second, and the change in the second quantity ultimately leads to an additional change in the first. A negative feedback is one in which the initial perturbation is weakened by the changes it causes; a positive feedback is one in which the initial perturbation is enhanced. In
the IPCC fifth Assessment Report, Working Group III contribution to the IPCC fifth Assessment Report - Mitigation to
Climate Change Technical Summary Final Draft, a somewhat narrower definition is often used in which the climate
quantity that is perturbed is the global mean surface temperature, which in turn causes changes in the global radiation
budget. In either case, the initial perturbation can either be externally forced or arise as part of internal variability (IPCC,
2014a, p. 1450).
3 The Challenge of a Changing Environment