Ever since the industrial revolution, the concentration of GHGs in the atmosphere is increasing, considerably affecting all forms of life on earth including biodiversity. The causes responsible for this phenomenon are the lack of alternative sources of energy, the overuse of fossil fuels, and the absence of alternative public transportation options. On the other hand, the insufficient adaptation to climate change is another cause which results from the lack of coordination and awareness and the unavailability of data.
Biodiversity in the Arab countries, already deteriorating, will be further damaged by intensifying climate change. A 2°C rise in temperature will make extinct up to 40% of all the species. The Arab countries have many unique formations that are especially vulnerable to climate change risk, such as the cedar forests in Lebanon and Syria, the mangroves in Qatar, the reed marshes of Iraq, the high mountain ranges of Yemen and Oman, and the coastal mountain ranges of the Red Sea (AFED, 2009).
In Lebanon, climate change has yet to be considered as a high priority by national authorities. However, consequences are being felt even if at low degrees. The manifestation of hotter summers, reduced and more irregular winter rainfall which is more likely to fall than snow (high temperatures causing more evaporation than infiltration) and the ensuing reduction of water resources are obvious social and environmental impacts of climate change.
Lebanon’s high altitudes, which provide refuges for many specialized species and niche ecosystems, will undoubtedly witness distribution shifts and in some cases disappearance of species. Two coniferous tree species, the cedar of Lebanon and the Silician fir reach their southernmost distribution limit in Lebanon and their distribution range will recede with increasing temperature to higher latitudes and altitudes in the region (AFED, 2009).
Ecosystems that comprise drought resistant species will adapt more easily to climate change compared to other ecosystems. Warmer climates are expected to cause an increase in rodents (field mice, house mice, rats etc.) all through the Lebanese territories. This phenomenon will eventually lead to an increase in rodent predators such as jackals, foxes, stone martins, etc. On the other hand, marginal mammals will become extinct due to the loss of habitat and food. This is the case for otters (Lutra lutra) (such as those in the Aammiq wetlands) and other mammals that depend on water bodies whose habitat will be harshly reduced due to the decrease in water resources (MoE, 2009). Increased temperatures will also cause the spread and proliferation of insect pests and disease vector populations. Climate change can also cause a shift of bioclimatic zones to higher altitudes which will mainly affect various reptiles and amphibians (Farajallah, 2008).
Other climate change impacts include modifications in 1) population physiology, 2) ecosystem phenology, and 3) geographical distribution of species.
Trends and routes of migration of birds will also be disturbed. Furthermore, bird populations whose distribution is restricted by cold temperatures will be forced to expand beyond their natural number with warmer temperatures. Inspections of the Lebanese avifauna suggest that few bird species from hot desert climate have started to colonize the vulnerable zone of the semi-arid Qaa by competing with native avifaunal species (SOER, 2010). The arrival of numerous new semi-desertic bird species in Lebanon is expected to occur (SOER, 2010).
In addition, increased temperatures will allow some plant species to become resistant to herbicides and pesticides.