The impacts of climate change | the global level

Scientists agree that the impacts of climate change are real but will be variable across the globe. Knowledge of impacts will allow policy makers to define actions for mitigation of climate change (that is, moving towards a low carbon society), and adaptation to climate change (that is, building resilience to the phenomenon).

Climate change is difficult to forecast with any real certainty. The oceans and atmosphere form a complex dynamic oscillating system. Many of the feedback mechanisms that act to regulate this system are still poorly understood. The Intergovernmental Panel on Climate Change [IPCC] was formed to investigate the influence of human action on future climate and inform policy makers of the likely impacts of forecast climate change on human societies.

Recent research suggests that these will be the more likely impacts due to climate change:

  • Changes in global temperature in the range 1.8 to 4.0 C by 2100;
  • Increases in sea level between 0.28 and 0.43 m by 2100;
  • Changes in precipitation patterns.

Some area of the planet are more vulnerable than others, however the repercussions of the impacts on vulnerable countries will be felt across all nations, with increases in displaced people, increased aid requirements and disruptions to trade.

The consequence in the Polar regions

Polar regions are very vulnerable to climate change and current ecosystems are unlikely to be able to adapt. Climate change is expected to be largest and most rapid in the polar regions with consequent impacts on natural and human systems. Evidence of change is already apparent in the reduced ice thickness and some changes in ecosystems. Only few weeks ago the lowest ever recorded sea ice minimum have been registered  [16th September 2012]. More importantly changes in the polar regions could lead to more significant changes across the rest of the globe and may continue for many centuries.

Satellite-based microwave images of the sea ice cover provide a reliable tool for continuously monitoring changes in the extent of the Arctic ice cover since 1979. This visualization shows the annual Arctic sea ice minimum from 1979 to 2010.

Arctic Sea Ice Extent
Evolution of the average sea ice extent for the month of July since 1979. A record low was reached in 2011.
Source: National snow and Ice Data Center

The consequences in Africa

In Africa adaptive capacity is low and the vulnerability to climate change is high because a large percentage of the population relies on rain-fed agriculture. Vulnerability to droughts and floods is particularly high. In most climate scenarios grain yields are forecast to drop, leading to reduced food security. Other impacts include:

  • Increased desertification due to reductions in average rainfall
  • Extinctions of plant and animal species, with impacts on local economies
  • Coastal inundation affecting various countries, including Egypt, Gambia, Senegal and others
  • Increasing drought leading to increased water stress

The consequences in Asia

In Asia there are many countries that are vulnerable to the impacts of climate change and, as in Africa, adaptive capacity is low in many cases. The more developed countries in Asia have a better adaptive capacity. Across Asia there are significant changes predicted in agricultural productivity. Tropical, arid and temperate areas are likely to see reduced productivity, due to flooding, seawater inundation and increasing risk of drought. Northern areas conversely may see increased food production. Other likely impacts include:

  • Increased risk of extreme events such as cyclones in temperate and tropical Asia
  • Sea level rise would displace tens of millions in temperate and tropical Asia
  • Risk to mangroves swamps and coral reefs
  • Changes in water availability
  • Increased risk from disease and increased risk of heat stress
  • Additional pressure on biodiversity

The consequences in Europe

Most countries in Europe are fairly well placed to adapt to climate change, but there are significant impacts expected:

  • Reduction of the numbers of mountain glaciers
  • Increased risk of reduced water availability in summer, particularly in southern Europe
  • Improvements in crop productivity
  • Increased risk of river flooding and increased risk of coastal flooding, with significant impacts on settlements, business and ecosystems
  • Loss of northern and highland habitats
The figure shows a comparison of current vegetation zones at a hypothetical dry temperate mountain site with simulated vegetation zones under a climate-warming scenario. Mountains cover about 20% of the Earth’s continents and serve as an important water source for most major rivers. Paleologic records indicate that climate warming in the past has caused vegetation zones to shift to higher elevations, resulting in the loss of some species and ecosystems. Simulated scenarios for temperate-climate mountain sites suggest that continued warming could have similar consequences. Species and ecosystems with limited climatic ranges could disappear and, in most mountain regions, the extent and volume of glaciers and the extent of permafrost and seasonal snow cover will be reduced. Resources for indigenous populations and recreational activities would be disrupted.
Source: GRID-Arendal

The consequences in South America

Many of the countries in Latin America are vulnerable to climate change because of the lack of adaptive capability in human systems. Populations are particularly vulnerable to extreme events. Water resources are expected to suffer significant impacts, with the loss of glaciers and the increased risk of flooding and drought. Other impacts include:

  • Reduction in crop yields in many areas
  • Increased range of infectious diseases
  • Increased sea level, affecting coastal settlements and human infrastructure
  • Increased intensity of tropical storms, increasing risks to life, property and ecosystems

The consequences in North America

North America has much better adaptive capabilities and is less vulnerable to the impacts of climate change. Some increases in crop productivity are forecast, at least in the short term. Other impacts include:

  • Some additional stress on water supply
  • Increased risks to some ecosystems e.g. alpine tundra and cold water ecosystems
  • Increased intensity of tropical storms leading to coastal erosion and loss of property in coastal areas
  • Possible increase in spread of vector-borne infectious diseases

Here you have the big picture of how our climate might change in the future due to our actions.

What do you think? Are you concerned about the effects on the environment of climate change?

The text and the images of the present post are reproduced with the permission of De Montfort University, being part of the MSc in Climate Change and Sustainable Development run by IESD

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