Over the past few decades, evidence has mounted that planetary-scale changes are occurring rapidly. These are, in turn, changing the patterns of forcings and feedbacks that characterize the internal dynamics of the Earth System. Key indicators, such as the concentration of CO2 in the atmosphere, are changing dramatically, and in many cases the linkages of these changes to human activities are strong. It is increasingly clear that the Earth System is being subjected to a wide range of new planetary-scale forces that originate in human activities, ranging from the artificial fixation of nitrogen and the emission of greenhouse gases to the conversion and fragmentation of natural vegetation and the loss of biological species. It is these activities and others like them that give rise to the phenomenon of global change.
Some facts about climate change
The Intergovernmental Panel on Climate Change (IPCC) fourth assessment report (2007) reliably indicates that we are facing an unavoidable increase in mean global temperature of between 1.1°C and 6.4°C by the end of the 21st century. The present trends in greenhouse gas emissions unfortunately means that the temperature increase is likely to reach the higher estimates. The consequences of this are dramatic. An increase in mean global temperatures above 2°C is projected to cause major changes in ecosystem functions and services and threaten the livelihoods of the people who depend on them, as well as increasing food insecurity and conflicts. In addition, approximately 20-30% of species assessed so far are likely to be at increased risk of extinction if increases in global average warming exceed 1.5-2.5°C (relative to 1980-1999).
In the IPCC report the major long-term changes observed are highlighted:
- Artic temperature and ice changes.
- Widespread changes in precipitation amounts, with drying trends in the Sahel, Mediterranean, southern Africa and southern Asia.
- Ocean salinity changes.
- Wind patterns changes, with the strengthening of the mid-latitude westerly winds in both hemispheres.
- Extreme weather changes including more intense and longer droughts over wider areas since 1970; more frequent heavy precipitation events over most land areas; more frequent heat weaves; and a higher intensity of tropical cyclones.
Deforestation accounts for up to one-third of global greenhouse gas emissions. The degradation and deforestation of tropical forests is a highly complex phenomenon caused by many factors. At the local level, it is fuelled by rural poverty. At the national and global levels, it is fuelled by population growth, economic development, agricultural expansion, mining, and logging as well as by indirect factors such as agricultural subsidies, investment in infrastructure, unclear land tenure, weak government surveillance, demand for timber and non-timber forest products and market pressure on land conversion.
The rural poor, disadvantaged communities and women are particularly vulnerable to the adverse effects of climate change, including climate variability and weather extremes, as their livelihoods often rely on climate-sensitive sectors like agriculture and local natural resources. This might hinder the achievement of development and poverty-reduction goals, unless vulnerable countries and communities are assisted in enhancing their adaptive capacity. Therefore, the international community should work on protecting and enhancing the natural services that support local livelihoods and helping vulnerable communities expand the range of options for coping with and adapting to climate variability and change.
Large-scale forest wildfires are among the most direct and immediate consequences of climate change on Mediterranean forests. The impacts of climate change combined with changes in land uses and the inappropriate management of forests encourage an increase in the frequency, intensity and extent of the fires. This trend was mainly observed in the northern shores of the Mediterranean region (e.g. Portugal, southern France, Spain, Italy and Greece) over the last two decades. If these conditions extend to the southern areas, the consequences regarding the forest ecosystems of the entire Mediterranean basin will be dramatic.
The world has a wide range of solutions that will help combat climate change. Protecting and better managing our natural resources is a cost-effective and efficient way to stabilize greenhouse gas emissions while we make the transition to a sustainable, low-carbon world in the coming decades. Natural resources can also help us adapt to the impacts of climate change we are already facing. It is an opportunity we cannot afford to let pass.