Temperature rise

The IPCC predicts a rise in annual mean surface temperatures of between 1.4 and 5.8ºC over the period 1990 to 2100. A mid-range temperature rise scenario will have a devastating effect on food security not only in the tropical and sub-tropical regions of the world but also in the mid-latitudes. As the British Foreign Minister stated in October 2006, “[t]emperature rises of just 2-3 degrees will see crop yields in Africa, the Middle East and South Asia fall by as much as 30 to 40 percent.” Higher average temperatures will also stimulate the emergence and re-emergence of pests and diseases, and increase the vectors that carry disease.

Ice melt

1.7 billion people currently live in water-stressed countries but this number is expected to increase to 5 billion by 2025. Retreating glaciers and snowlines will increase variability in river flow, diminish consistent water supplies and exacerbate these stresses. The South Asian sub-continent and South America are both likely to suffer. Sea level rise is predicted to be between 0.09 and 0.88 metres over the period 1990 to 2100. Higher sea levels will have catastrophic implications for small Pacific states and low-lying countries such as Bangladesh, and also for all major coastal cities.

Extreme weather events

Increased precipitation will lead to more extensive flooding. These impacts will be accentuated in areas where drought has hardened the earth and increased the likelihood of flash floods. Flooding leads to soil erosion and results in landslides which cause extensive damage to dwellings and livelihoods. The Asian monsoon is sensitive to small temperature changes and stands to wreak havoc across the sub-continent. In July 2005, Mumbai received 37 inches of rain in 24 hours, the largest downpour recorded in an Indian city. Increased incidence of heat waves will result in illness and death, especially amongst the old and very young. Increased storm surges will have a significant impact on coastal settlements.

Length of growing season

The length of a growing season depends on the first and last day of a base temperature above which plants will grow. Increased climate variability is currently leading to unpredictable changes in the length of the growing seasons for all sorts of crops all around the world. This is the major concern not only for farmers whose livelihoods depend on consistent crop yields, but also to the billions of people living in poverty who are dramatically affected by variability in food prices. Climate variability can also play havoc with the natural breeding cycle of insects and animals, and the balance of the ecosystems that they live within.

Acidification of the oceans

The ocean absorbs carbon dioxide from the atmosphere, forms carbonic acid and reduces the pH of the water. The oceans have already absorbed fifty percent of the carbon dioxide that we have produced since the industrial revolution. The lowering of the ocean’s pH has a significant impact on the ability of small marine organisms to form shells. These organisms play a crucial role at the bottom of the marine food chain. Acidification also damages coral. Impacts on marine bio-diversity and the coral reefs have significant implications for the communities who are dependent on already depleted fisheries for their subsistence and livelihood.

Human security

Indirect impacts have further implications for developing countries. A discussion paper written for the US Defense Department presents a scenario where the effects of climate change and the resultant reduction in the environment’s ‘carrying capacity’ in terms of food, water and energy quickly lead to security issues. It is easy to see that when food and water security are compromised, the likelihood of conflict and social insecurity increases.

Energy Security

Energy security is also threatened by extreme weather events that undermine the stability of ports and drilling rigs. Glacier retreat and ice cap melt will impact on hydro-electricity and melting permafrost will weaken pipelines. Energy insecurity jeopardises the social and economic services that improve people’s capabilities and ameliorate the affects of poverty. The cumulative effect of all these factors will be to undermine the very basis of governance and productivity. With less capital and more desperate circumstances, the fabric of civilisation itself becomes threatened. Consequently, action and support from developed countries on climate change has to be seen in the context of an overall responsibility to promote sustainable development and to fight poverty as expressed in the Millennium Development Goals.

Peoples’ perceptions

Climate change is a global challenge that requires immediate individual and collective action. Unfortunately, it is a self-evident fact that information alone is unable to motivate action. Public opinion surveys all around the world consistently indicate that the majority of people are concerned about climate change, but they also find that people feel unsure about what it means to them personally and what should be done about it. Despite concern, often only a limited number of respondents are actually taking concerted action to prevent climate change, less still are taking actions that are actually consistent and effective. So while there is widespread acknowledgement of the threat, there is little substantive engagement with the problem. This inertia between problem and action underlines the importance of enabling leadership at all levels of society to better motivate effective engagement on this critical issue.