A new study by NOAA - the US National Oceanic and Atmospheric Administration - has highlighted that climate change is a major contributor to more frequent Mediterranean droughts. According to the study in the last 20 years, 10 of the driest 12 winters have taken place in the lands surrounding the Mediterranean Sea. Water security, food security, and increasing wildfire frequency and intensity has the potential to destabilize the region producing conflicts over use of increasingly scarce water resources.
"The magnitude and frequency of the drying that has occurred is too great to be explained by natural variability alone,” said Martin Hoerling, Ph.D. of NOAA’s Earth System Research Laboratory in Boulder, Colorado, lead author of a paper published online in the Journal of Climate this month. “This is not encouraging news for a region that already experiences water stress, because it implies natural variability alone is unlikely to return the region’s climate to normal.”
The scientists attributed roughly half the increased dryness trend of 1902-2010 to Climate change from greenhouse gases. The other processes involved were not identified by the study. Accurate rainfall records stretch back to 1902 for the study.
"Anthropogenic greenhouse gas and aerosol forcing are key attributable factors for this increased drying, though the external signal explains only half of the drying magnitude. Furthermore, sea surface temperature (SST) forcing during 1902-2010 likely played an important role in the observed Mediterranean drying, and the externally forced drying signal likely also occurs through an SST change signal." says the article abstract.
There was a strong correlation between the observed increase in winter droughts and the projections of climate models that include known increases in greenhouse gases. Both climate modeling and observations show a sudden shift to drier conditions beginning in the 1970s.
Warming and drought in the Mediterranean region is being driven by increases in sea surface temperature patterns. This increases drought-conducive weather patterns around the Mediterranean. The scientists found that the timing of ocean temperature changes coincides closely with the timing of increased droughts.
"Climate models subjected to a uniform +0.5°C warming of the world oceans induce eastern Mediterranean drying, but fail to generate the observed wide-spread Mediterranean drying pattern. For a +0.5°C SST warming confined to tropical latitudes only, a dry signal spanning the entire Mediterranean region occurs. The simulated Mediterranean drying intensifies further when the Indian Ocean is warmed +0.5°C more than the remaining tropical oceans, an enhanced drying signal attributable to a distinctive atmospheric circulation response resembling the positive phase of the North Atlantic Oscillation." the scientists say in the article abstract.
The NOAA study agrees with a French study - Anthropogenic climate change over the Mediterranean region simulated by a global variable resolution model - published in 2004 by A.L. Gibelin and M. Déqué from the Météo-France, Centre National de Recherches Météorologiques. This 2004 study concluded in the abstract that "temperature and precipitation responses predict a warming and drying of the Mediterranean region. A comparison with the coupled simulation and forced low-resolution simulation shows that this pattern is robust. The decrease in mean precipitation is associated with a significant decrease in soil wetness, and could involve considerable impact on water resources around the Mediterranean basin."
Winter rains are an important resource for agriculture in the region. Increasing drought is likely to impact agriculture and food security putting pressure on food prices. Water security for human consumption and agriculture may become more of an issue.
Water Security and the Example of Darfur
Potential conflict over water resources is increasingly being discussed. The example of Darfur in Sudanese Africa is often raised as a climate change fueled conflict over scarce water resources. While water scarcity due to global warming was one driver of the conflict, political and social drivers were also important factors in the conflicts.
Un Secretary General Ban Ki Moon described the beginings of the conflict in a Washington Post artice from June 2007:
"Amid the diverse social and political causes, the Darfur conflict began as an ecological crisis, arising at least in part from climate change. Two decades ago, the rains in southern Sudan began to fail. According to U.N. statistics, average precipitation has declined some 40 percent since the early 1980s. Scientists at first considered this to be an unfortunate quirk of nature. But subsequent investigation found that it coincided with a rise in temperatures of the Indian Ocean, disrupting seasonal monsoons. This suggests that the drying of sub-Saharan Africa derives, to some degree, from man-made global warming."
Temperatures in Darfur increased by an average 0.7 degrees between 1990 and 2005. The impacts were severe including the decline of flora and fauna with substantial migrations of herds south, conflicts between tribal groupings over water access and use, and extensive famines which in 1984 killed about 100,000 people, while several hundred thousand more barely survived by adapting through solidarity, consumption of wild plants and migration (displacement). (See Conference Transcription, Climate Change and Security in Africa, Paris, 20/01/2009)
Referring to the conflicts in Darfur, French President Nicolas Sarkozy said in 2008 "Climate change is already having a considerable impact on security. If we keep going down this path, climate change will encourage the immigration of people with nothing towards areas where the population do have something, and the Darfur crisis will be only one crisis among dozens of others."
Water remains a source of conflict in Darfur, with a major conference held in June 2011 to discuss the water situation and how to manage and adapt to sharing and use of this scarce resource.
With less precipitation and increasing drought periods water scarcity is already an issue in many countries bordering the Mediterranean. The European Commission is funding research from 2010 to 2013 on Water Availability and Security in Southern EuRope and the Mediterranean (WASSERMED). The project will research and analyse "ongoing and future climate induced changes in hydrological budgets and extremes in southern Europe, North Africa and the Middle East under the frame of threats to national and human security."
The Cyprus Institute has a research site on Climate Change, Hydro-conflicts and Human Security (CLICO) which has done preliminary reporting of climate projections for precipitation around the Mediterranean, Middle East and Sahel. With substantial drying predicted for the region some areas may see up to a 25% decrease in precipitation.
"there is growing evidence that climate induced changes in water resources have a strong potential to instigate conflicts and a growing consensus in the scientific community that climate change, in conjunction with other factors, poses a challenge to social stability" says a CLICO 2010 policy brief (Climate change, hydro-conflicts and human security: achievements of and gaps in current policies by Ecologic [Policy Brief, Apr 2010])
CLICOs research program is being funded to investigate the hydro-climatic hazards and devise policy responses for promoting peace and security under changing hydro-climatic conditions, to minimise conflict.
Drier, warmer climate means larger more intense Forest Fires
Increasing temperatures around the Mediterranean region, combined with drought will increase the intensity and frequency of forest fires. In 2009 Greece declared a state of emergency as huge fires reached the outskirts of Athens.
The Incidence of fires on the Iberian peninsula has doubled since the 1970s. In the Mediterranean Basin Forest Fires Are Becoming Larger and More Frequent according to research reported on Sciencedaily on October 24, 2011. Much of this change has been attributed to land use changes and depopulation of rural areas from the 1970s.
"The depopulation of rural areas resulted in the abandonment of agricultural spaces that had historically been interspersed among the forests. Because of this, in the space of a few years, spaces where there had previously been grain fields were invaded by highly flammable vegetation in a series of steps leading toward the Mediterranean forests," explained Professor Fernández Muñoz.
But other studies say climate change is a pivotal force in addition to landuse changes, resource overexploitation and pollution affecting forests. An international workshop held in Athens in 2008 co-organized by the WWF and IUCN on "Adaptation to Climate Change in Mediterranean Forest Conservation and Management" concluded that:
"Forest wildfires are among the most direct and immediate consequence of climate change upon Mediterranean forests. Climate change impacts, such as extended periods of high temperatures, the extreme meteorological phenomena (heat waves and strong winds), combined with land uses changes encourage the increase of frequency,
intensity and extent of fires. The described conditions are mainly observed in the northern areas of Mediterranean (Portugal, Greece, and Spain). If these conditions are extended in the southern areas, the consequences regarding the forest ecosystems of the entire Mediterranean basin will be dramatic."
Forests which are subjected to repeated fires over a few years are likely to lose biodiversity. A 2009 Sciencedaily report of a Cemagref paper (Repeated Fire And Drought: A Menace For Mediterranean Forests.)(Website) said that:
"Four successive dry years would appear to constitute a critical threshold in the resistance of forests to fire. Climate change, by intensifying the combination of fire and dryness, can only increase the fragility of ecosystems, which makes it difficult to foresee their condition over the mid and long term."
Sources:
- NOAA October 27, 2011 - NOAA study: Human-caused climate change a major factor in more frequent Mediterranean droughts
- Martin Hoerling, Jon Eischeid, Judith Perlwitz, Xiao Wei Quan, Tao Zhang, Philip Pegion, On the Increased Frequency of Mediterranean Drought, NOAA Earth System Research Laboratory, Boulder Colorado USA, Journal of Climate 2011 ; doi: 10.1175/JCLI-D-11-00296.1 (abstract)
- A.L. Gibelin and M. Déqué from the Météo-France, Centre National de Recherches Météorologiques, Anthropogenic climate change over the Mediterranean region simulated by a global variable resolution model (2004) in Climate Dynamics
Volume 20, Number 4, 327-339, DOI: 10.1007/s00382-002-0277-1 (abstract)
- IUCN 12 May 2008, Mediterranean forests under threat due to climate change
- Image of Europe by NOAA - Reds and oranges highlight lands around the Mediterranean that experienced significantly drier winters during 1971-2010 than the comparison period of 1902-2010.
- Image of Winter precipitation trends by NOAA - Winter precipitation trends in the Mediterranean region for the period 1902 - 2010.
- Image Fires in Greece by NASA taken in August 2007.
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