UN warns of climate impacts
The report, “Impacts, Adaptation, and Vulnerability”, is the second in a series of four that together comprise the 4th Assessment of the Intergovernmental Panel on Climate Change (IPCC), the most comprehensive scientific, economic, and social evaluation of climate change to date. Members of the IPCC are meeting this week in Brussels to finalize the text of the report.
The physical science component was issued in January, saying with near certainty that human activities are the cause of most of the observed global warming over the past fifty years, and projecting further warming over the next century.
The IPCC also refined projections of future temperature levels, estimating an increase of between 2 and 4.5 degrees Celsius before 2100, with a 3 degrees C rise the most likely.
As a result, the UN projects that sea levels will increase by 9cm to 88cm, droughts will become more widespread, flooding will increase, and extreme weather events will become more common.
The Impacts, Adaptation, and Vulnerability report focuses on specific impacts of warming on each region of the world as well as adaptation options, with an unbalanced picture of the future emerging.
According to the IPCC, those in developing countries and island states will suffer the most, while some northern countries may experience some benefits along with negative impacts.
“At least for a few decades there will be a few winners,” said IPCC head Rajendra Pachauri. But following the extended rise in temperatures predicted during this century, the impacts will leave no winners anywhere, he added.
Africa will be among the hardest hit areas, suffering reductions in available area for agriculture, severe water shortages, and desertification. Following floods and droughts, many are likely to face hunger and changes in food supplies, while major populations in the deltas of the Nile and Niger rivers will be threatened by sea level rises, the IPCC predicts.
In other regions, water stress, displacement of populations, changes in agricultural patterns, and increased drought, flooding and fires are projected.
Glaciers all over the world are expected to decline, or disappear in some cases. This will reduce the amount of fresh water available for people in many areas, and will also impact the availability of water for hydro power generation.
The Polar Regions are expected to see some of the most dramatic changes. This includes a loss of average Arctic sea-ice by between 22 and 33 percent by 2100. For Antarctica, projections range from a slight increase to an almost complete loss of summer sea ice. Melting of Arctic glaciers and ice caps, as well as the Greenland ice cap could have serious impacts.
The resulting rise in sea levels would affect the 1.5 billion people that live within 100 kilometres distance and 100 metres elevation of the coastline, says the IPCC. Depending on future greenhouse gas emissions, those areas are at risk from rising sea levels, more powerful storms, coastal flooding, damage to fisheries and saltwater intrusion into freshwater resources.
According to estimates the IPCC considers moderately likely, nearly five percent of the population of Bangladesh will face inundation if temperatures rise 2 C, the sea level increases 30 centimetres, and monsoon rainfall increases 18 percent.
A variety of health problems, including malaria, cholera, malnutrition, and heatstroke are expected to worsen with temperature increases. Climate change has already extended the range of mosquitoes and ticks and helped to spread disease. In the coming decades, such problems will be amplified and compounded with issues such as hunger and physical displacement, says the report.
“Adverse health impacts will be greatest in low-income countries,” says the report. “Those at greater risk include, in all countries, the urban poor, the elderly and children, traditional societies, subsistence farmers and coastal populations.”
Ecosystems around the world will also experience change, as temperature increases displace animal and plant species. Eastern sections of the Amazon rainforest could turn to savannah, threatening many species with extinction and causing further climate change, warns the IPCC.
Canada may be among the nations that experience increased crop yields and the opening up of new lands for agriculture, but dramatic long term changes in the Northern eco-systems and socio-economic impacts in other areas predicted by the report will outweigh those short term benefits.
The impacts predicted for North America include:
- ‘Dramatic increases’ in property value losses from severe weather events
- Sea level rises, tidal surges and flooding which have the “potential to severely affect transportation and infrastructure along the Gulf, Atlantic and northern coasts”
- Severe heat waves over parts of the United States and Canada
- Ozone related deaths increasing by 4.5 percent from the 1990s to the 2050s
- Large decreases in snowpack, earlier snowmelt, and more winter rains by mid-century
- Increased forest production, but with the dominant impacts in the second half of the century disruptions from pests and fires
- Forest areas burnt each summer in Canada could rise by between 74 and 118 percent by 2100 compared to now.
In short, the news is not good. The projected impacts of climate change are severe, with the potential to reduce quality of life and economic prosperity for billions around the world. While the IPCC acknowledges that some projections are subject to uncertainty, the core message is that if we continue along a path of increasing greenhouse gas emissions, we place every level of our society at risk.
When released, the IPCC report will be available here.