12.2.1 Climate Change: Definition and Impacts

Climate change is not a new phenomenon; it is an environmental reality that has affected human populations and the natural world for hundreds of thousands of years. What is new and troubling is the extreme rate of climate change and the fact that billions of global citizens are now affected by it. Island nations are sinking rapidly, sea level rise is forcing communities to migrate, extreme heat is turning arable land into desert, there are severe water shortages in India and northern China, and extreme weather events such as the Nok-Ten storm in Thailand that left 65 of the nation’s 77 provinces declared disaster zones are becoming more frequent; these and other environmental events are among the impacts of climate change.

According to the Intergovernmental Panel on Climate Change (IPCC), “There are many indicators of climate change. These include physical responses such as changes in the following: surface temperature, atmospheric water vapour, precipitation, severe events, glaciers, ocean and land ice, and sea level.” (Cubasch & al., 2013).

One study noted the ‘severe’ climate impacts that are possible scenarios in the 21st century:

1. By 2040, the average global temperature could rise 2.6°C (4.7°F) above 1990 levels.
2. The global sea level could rise by 0.52 m (1.7 ft).
3. Water availability could decrease significantly in the most affected regions at lower altitudes (dry tropics and sub-tropics), thereby affecting 2 billion people.
4. Developing nations at lower altitudes will be affected most severely because of their climate sensitivity and low adaptive capacity. Industrialized nations to the north, meanwhile, will experience clear net harm and must divert greater proportions of their wealth to combat climate change at home. (Gulledge, 2008)

A range of potentially destructive climate impacts have been described in scientific studies:

“Hazard: The potential occurrence of a natural or human-induced physical event or trend or physical impact that may cause loss of life, injury, or other health impacts, as well as damage and loss to property, infrastructure, livelihoods, service provision, ecosystems and environmental resources.

Exposure: The presence of people, livelihoods, species or ecosystems, environmental functions, services and resources, infrastructure, or economic, social, or cultural assets in places and settings that could be adversely affected.

Vulnerability: The propensity or predisposition to be adversely affected. Vulnerability encompasses a variety of concepts and elements including sensitivity or susceptibility to harm and lack of capacity to cope and adapt.

Impacts: Effects on natural and human systems. The impacts of climate change on geophysical systems, including floods, droughts and sea level rise, are a subset of impacts called physical impacts.

Risk: The potential for consequences where something of value is at stake and where the outcome is uncertain, recognizing the diversity of values. Risk is often represented as probability of occurrence of hazardous events or trends multiplied by the impacts if these events or trends occur.

Adaption: The process of adjustment to actual or expected climate and its effects. In human systems, adaption seeks to moderate or avoid harm or exploit beneficial opportunities.

Resilience: The capacity of social, economic and environmental systems to cope with a hazardous event or trend or disturbance, responding or reorganizing in ways that maintain their essential function, identity and structure, while also maintaining the capacity for adaption, learning, and transformation.” (IPCC, 2014).

Climate change projections for the 21st century are dramatic and irrefutable. Although variances will occur in terms of intensity in some regions, the general climate prognosis is certain with reference to weather extremes, sea level rise, rising heat levels, desertification, ocean acidification, human health threats, damage to habitat and species extinction. Another alarming trend noted by the United Nations and other authoritative bodies is the huge projected rise in climate refugee populations that governments will largely be unprepared to control or mitigate. The U.N. has cited an estimate that there will be 200 million climate change refugees by 2050.