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Chapter 3: Climate Change
Climate Change
Introduction
Climate change is an overarching global challenge.
Responding effectively to climate change is both urgent
and long term. It is urgent in that our actions and
responses in the next 5–15 years may effectively lock in
large-scale and irreversible planetary changes over this
and subsequent centuries. The December 2015 Paris
Agreement sets the international agenda for addressing
this challenge. However, it must be addressed at national
and sub-national levels and by cities, businesses and
communities. At national level, the National Policy Position
(DECLG, 2014) and the Climate Action and Low Carbon
Development Act 2015 provide the policy framework for
actions. In combination with EU-level emissions targets for
2020 and 2030, these specify the short-term actions and
longer-term strategy to advance mitigation and adaptation
actions. A brief overview of the science of climate change,
the response options and policy context is provided here.
The nature and scale of the challenges that Ireland faces in
addressing climate change are also outlined.
Scientific Understanding
The scientific understanding of climate change is
robust. Warming of the climate system is unequivocal
and the human influence on this is clear.
The impacts of changes to the atmosphere on climate are
well known. Major volcanic eruptions such as Pinatubo
(1991) or Krakatoa (1883) produced plumes of fine
particles which shaded and cooled the Earth, reducing
subsequent summer temperatures by between 0.5°C and
1.0°C. Similarly, air pollutants typically act to temporarily
“cool” the Earth. They also impact on human health
and cause environmental damage (see Chapter 2). The
accumulation in the atmosphere of relatively stable and
inert gases, such as carbon dioxide, that trap energy is
the key threat to our climate (Figure 3.1). In 2015, the
atmospheric concentration of carbon dioxide reached
400 ppm, a level that has not occurred for at least
800,000 years. It is one of the many changes that the
Intergovernmental Panel on Climate Change (IPCC) has
described as unprecedented for centuries to millennia
(IPCC, 2014a,b).