Consequences
The natural greenhouse effect does not threaten our climate - in fact its heating effect allows life on Earth as we know it. However, the enhanced greenhouse effect due to anthropogenic GHG emissions and the corresponding worrying rate of global warming are believed to have severe consequences for our society.
The majority of scientific evidence indicates that our climate is already changing and that we should expect extreme weather events (such as storms, floods, and heat waves) to increase in frequency and intensity, as well as to cause increasing global temperatures and rising sea levels.
This could lead to other indirect effects such as the spreading of tropical diseases to new regions and forced migrations of entire populations (the low lying and cyclone-prone nation of Bangladesh being a prime example). The negative impacts will be strongest in low-income countries, which are less able to take the necessary adaptation measures.
Source: NASA, Tomas Castelazo, Bidgee
As ecosystems will have trouble adapting to these rapid changes, severe degradation of ecosystems will occur with risk of total ecosystem collapses. This degradation triggers more disasters and increases the vulnerability of nature and of societies to climate change and disasters since many ecosystems serve as a buffer for climate change impacts (e.g. coral reefs reduce the impacts of sea surges and tropical storm waves before they reach the shoreline, forests can act as a carbon sink, mangrove forests act as revetments or dikes, etc.). The fact that this problem is arising while at the same time we are also pushing the boundaries of our natural ecosystems due to an increase in world population and rising consumption levels, is especially disquieting.
“The resilience of many ecosystems is likely to be exceeded by 2100 by an unprecedented combination of change in climate, associated disturbances (e.g., flooding, drought, wildfire, insects, ocean acidification), and other global change drivers (e.g., land-use change, pollution, over-exploitation of resources) (high confidence).”
~ IPCC Fourth Assessment Report (AR4)
In order to keep these negative consequences under control, a long-term rise in average global temperature of 2 ˚C compared to the pre-industrial level is generally seen as the upper limit, beyond which climate changes becomes catastrophic and irreversible. However, according to a recent report by the International Energy Agency, the path we are currently on is more likely to result in a temperature increase of between 3.6 ｰC and 5.3 ｰC. To put this into perspective, the Earth is now approximately 5 ˚C warmer than during the last ice age.
Sources:
EU Climate Change Expert Group ‘EG Science’ (2008). The 2 ˚C target. Information Reference Document.
Intergovernmental Panel of Climate Change (2007). Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.)]. IPCC, Geneva, Switzerland, 104 pp. Available on: http://www.ipcc.ch/publications_and_data/ar4/syr/en/contents.html
International Energy Agency (2013). World Energy Outlook Special Report, Redrawing the Energy Energy-Climate Map. OECD/IEA, Paris, France, 134 pp. Available on: http://www.worldenergyoutlook.org/energyclimatemap/#d.en.36900
UNEP (2009). The Role of Ecosystem Management in Climate Change Adaptation and Disaster Risk Reduction. Copenhagen Discussion Series. Available on: http://www.unep.org/climatechange/Portals/5/documents/UNEP-DiscussionSeries_2.pdf
As ecosystems will have trouble adapting to these rapid changes, severe degradation of ecosystems will occur with risk of total ecosystem collapses. This degradation triggers more disasters and increases the vulnerability of nature and of societies to climate change and disasters since many ecosystems serve as a buffer for climate change impacts (e.g. coral reefs reduce the impacts of sea surges and tropical storm waves before they reach the shoreline, forests can act as a carbon sink, mangrove forests act as revetments or dikes, etc.). The fact that this problem is arising while at the same time we are also pushing the boundaries of our natural ecosystems due to an increase in world population and rising consumption levels, is especially disquieting.
“The resilience of many ecosystems is likely to be exceeded by 2100 by an unprecedented combination of change in climate, associated disturbances (e.g., flooding, drought, wildfire, insects, ocean acidification), and other global change drivers (e.g., land-use change, pollution, over-exploitation of resources) (high confidence).”
~ IPCC Fourth Assessment Report (AR4)
In order to keep these negative consequences under control, a long-term rise in average global temperature of 2 ˚C compared to the pre-industrial level is generally seen as the upper limit, beyond which climate changes becomes catastrophic and irreversible. However, according to a recent report by the International Energy Agency, the path we are currently on is more likely to result in a temperature increase of between 3.6 ｰC and 5.3 ｰC. To put this into perspective, the Earth is now approximately 5 ˚C warmer than during the last ice age.
Sources:
EU Climate Change Expert Group ‘EG Science’ (2008). The 2 ˚C target. Information Reference Document.
Intergovernmental Panel of Climate Change (2007). Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.)]. IPCC, Geneva, Switzerland, 104 pp. Available on: http://www.ipcc.ch/publications_and_data/ar4/syr/en/contents.html
International Energy Agency (2013). World Energy Outlook Special Report, Redrawing the Energy Energy-Climate Map. OECD/IEA, Paris, France, 134 pp. Available on: http://www.worldenergyoutlook.org/energyclimatemap/#d.en.36900
UNEP (2009). The Role of Ecosystem Management in Climate Change Adaptation and Disaster Risk Reduction. Copenhagen Discussion Series. Available on: http://www.unep.org/climatechange/Portals/5/documents/UNEP-DiscussionSeries_2.pdf