Impacts and sensitivity

Changes in temperature, sea level, wind and rainfall patterns are not trivial events that can be placed in the background of our daily concerns. We only have to look at El Niño events that periodically visit us to see how these changes are able to wreak havoc on our resources and our adaptive capacity as a national community. Many of these changes and impacts have already been documented as occurring in this decade alone.

• Warm seas chafe our coral reefs, these nurseries of marine life, causing them to bleach and die.
• Highly variable rainy seasons drive the incidence and trajectory of mosquito borne diseases such as malaria and dengue.
• Expanding oceans are already invading our freshwater aquifers, mangrove ecosystems, and rice water supply.

We still do not know if typhoons in a warmer world will be more fierce and frequent. We are left guessing as to how the monsoons, those dependable guests of ours, will behave before the vagaries of a changing climate.

The sensitivity of natural and human systems to these changes or "climate-related stimuli" will vary according to the nature, magnitude and frequency of the changes. Higher sensitivity suggests the greater possibility of prolonged or irreversible damage. Among the natural systems that are expected to be climate-sensitive are coral reefs, mangroves, and forest ecosystems.

Human systems likely to be affected are agriculture and fisheries, public health, freshwater resources, and the like.

Some of the more serious impacts listed in the IPCC's Third Assessment Report (WGII) include:

Adaptation

Adaptation is necessary to prevent potential damages, harness possible benefits and opportunities, and manage the consequences of climate change and variability. To some extent, natural and human systems can and do adapt autonomously to these changes. The possibility however of large scale, prolonged impacts demands adaptation planning to supplement these innate adaptive mechanisms.

Much of this planning can draw from the experience of coping with current climate variability and extremes. These changes, after all, can be the prelude of what is in store for us in a warmer world. Adaptation planning can likewise converge with related efforts in disaster mitigation and land use planning. It can avoid the pitfall of maladaptation, an example of which locates development in areas of high risk due to quick financial gains, neglect of climate and other environmental factors, misinformation, and the like.

Examples of adaptation measures are:

Vulnerability

The vulnerability of natural and human systems will depend on their climate impact exposure, climate sensitivity, and the strength of their adaptive capacity.

Poorer communities and nations are less capable of adjusting to these changes, which thus makes them more vulnerable than those with access to resources and technology. Vulnerability is therefore differentiated because adaptive capacity itself will vary according to the adverse or beneficial influence of factors such as climate risk exposure, land use, population growth, economic security, education, culture, public health, environmental pollution, and other related adaptation drivers.

Such differentiated vulnerability only exacerbates the disparity between developed and developing countries, which disparity is projected to become more severe with the global increase in temperature. This regressive outcome is possible also because of feedback mechanisms that amplify the erosion of a poor community's adaptive capacity due to the hazards posed by climate change itself.

The human or societal sectors of concern under adaptation and vulnerability are: