Impacts of Climate Change

Lesser and Greater Emission  | Likely Impacts of Climate Change  | Water Resources  | Forestry  | Agriculture


Climate change is one of the most fundamental challenges ever to confront humanity. Its adverse impacts are already being seen and may intensify exponentially over time if nothing is done to reduce further emissions of greenhouse gases. Decisively dealing NOW with climate change is key to ensuring sustainable development, poverty eradication and safeguarding economic growth. Scientific assessments indicate that the cost of inaction now will be more costly in the future. Thus, economic development needs to be shifted to a low-carbon emission path.

In 1992, the United Nations Framework Convention on Climate Change (UNFCCC) was adopted as the basis for a global response to the problem. The Philippines signed the UNFCCC on 12 June 1992 and ratified the international treaty on 2 August 1994. Presently, the Convention enjoys near-universal membership, with 194 Country Parties.

Recognizing that the climate system is a shared resource which is greatly affected by anthropogenic emissions of greenhouse gases, the UNFCCC has set out an overall framework for intergovernmental efforts to consider what can be done to reduce global warming and to cope with whatever temperature increases are inevitable. Its ultimate objective is to stabilize greenhouse gas concentrations in the atmosphere at a level that will prevent dangerous human interference with the climate system.

Countries are actively discussing and negotiating ways to deal with the climate change problem within the UNFCCC using two central approaches. The first task is to address the root cause by reducing greenhouse gas emissions from human activity. The means to achieve this are very contentious, as it will require radical changes in the way many societies are organized, especially in respect to fossil fuel use, industry operations, land use, and development. Within the climate change arena, the reduction of greenhouse gas emissions is called mitigation.

The second task in responding to climate change is to manage its impacts. Future impacts on the environment and society are now inevitable, owing to the amount of greenhouse gases already in the atmosphere from past decades of industrial and other human activities, and to the added amounts from continued emissions over the next few decades until such time as mitigation policies and actions become effective. We are therefore committed to changes in the climate. Taking steps to cope with the changed climate conditions both in terms of reducing adverse impacts and taking advantage of potential benefits is called adaptation.


What if the emissions are less or greater?

Responses of the local climate to the mid-range compared to the high- and low-range scenarios are as shown in Fig. 22 below. Although there are vast differences in the projections, the so-called temperature anomalies or difference in surface temperature increase begin to diverge only in the middle of the 21st century. As has already been stated, the climate in the next 30 to 40 years is greatly influenced by past greenhouse gas emissions. The long lifetimes of the greenhouse gases already in the atmosphere, with the exception of methane (with a lifetime of only 13 years), will mean that it will take at least 30 to 40 years for the atmosphere to stabilize even if mitigation measures are put in place, not withstanding that in the near future, there could be some off-setting between sulfate aerosols (cooling effect) and the greenhouse gas concentrations (warming effect).


Likely impacts of climate change

A warmer world is certain to impact on systems and sectors; although, magnitude of impacts will depend on factors such as sensitivity, exposure and adaptive capacity to climate risks. In most cases, likely impacts will be adverse. However, there could be instances when likely impacts present opportunities for potential benefits as in the case of the so-called carbon fertilization effect in which increased carbon dioxide could lead to increased yield provided temperatures do not exceed threshold values for a given crop/cultivar.


Water Resources

In areas/regions where rainfall is projected to decrease, there will be water stress (both in quantity and quality), which in turn, will most likely cascade into more adverse impacts, particularly on forestry, agriculture and livelihood, health, and human settlement.

Large decreases in rainfall and longer drier periods will affect the amount of water in watersheds and dams which provide irrigation services to farmers, especially those in rain fed areas, thereby, limiting agricultural production. Likewise, energy production from dams could also be rendered insufficient in those areas where rainfall is projected to decrease, and thus, could largely affect the energy sufficiency program of the country. Design of infrastructure, particularly of dams, will need to be re-visited to ensure that these will not be severely affected by the projected longer drier periods.

In areas where rainfall could be intense during wet periods, flooding events would follow and may pose danger to human settlements and infrastructure, in terms of landslides and mudslides, most especially, in geologically weak areas. Additionally, these flooding events could impact severely on public infrastructure, such as roads and bridges, including classrooms, evacuation centers, and hospitals.

Adaptive capacity is enhanced when impact and vulnerability assessments are used as the basis of strategic and long-term planning for adaptation. Assessments would indicate areas where critical water shortages can be expected leading to possible reduction of water available for domestic consumption, less irrigation service delivery, and possibly, decreased energy generation in dams. Note that the adverse impacts would cascade, so that long-term pro-active planning for these possible impacts is imperative in order to be able to respond effectively, and avoid maladaptations. A number of adaptation strategies should be considered. Among the wide array of cost effective options are rational water management, planning to avoid mismatch between water supply and demand through policies, upgrading/rehabilitation of dams where these are cost-effective, changes in cropping patterns in agricultural areas, establishing rain water collection facilities, where possible, and early warning systems.



Changes in rainfall regimes and patterns resulting to increase/decrease in water use and temperature increases could lead to a change in the forests ecosystem, particularly in areas where the rains are severely limited, and can no longer provide favorable conditions for certain highly sensitive species. Some of our forests could face die-backs. Additionally, drier periods and warmer temperatures, especially during the warm phase of El Nino events, could cause forest fires. A very likely threat to communities that largely depend on the ecological services provided by forests is that they may face the need to alter their traditions and livelihoods. This change in practices and behavior can lead to further degradation of the environment as they resort to more extensive agricultural production in already degraded areas.

Adverse impacts on forestry areas and resources could be expected to multiply in a future warmer world. The value of impact and vulnerability assessments could not be underscored. These assessments would help decision makers and stakeholders identify the best option to address the different impacts on forest areas, watersheds and agroforestry. Indigenous communities have to plan for climate-resilient alternative livelihoods. Thus, it is highly important to plan for rational forest management, particularly, in protected areas and in ancestral domains. One of the more important issues to consider is how to safeguard livelihoods in affected communities so as not to further exacerbate land degradation. Early warning systems in this sector will play a very important role in forest protection through avoidance and control/containment of forest fires.



Agriculture in the country could be severely affected by temperature changes coupled with changes in rain regimes and patterns. Crops have been shown to suffer decreases in yields whenever temperatures have exceeded threshold values and possibly result to spikelet sterility, as in the case of rice. The reduction in crop yield would remain unmitigated or even aggravated if management technologies are not put in place. Additionally, in areas where rain patterns change or when extreme events such as floods or droughts happen more often, grain and other agricultural produce could suffer shortfalls in the absence of effective and timely interventions. Tropical cyclones, particularly if there will be an increase in numbers and/or strength will continue to exert pressure on agricultural production.

Moreover, temperature increases coupled with rainfall changes could affect the incidence/outbreaks of pests and diseases, both in plants and animals. The pathways through which diseases and pests could be triggered and rendered most favorable to spread are still largely unknown. It is therefore important that research focus on these issues.

In the fisheries sub-sector, migration of fish to cooler and deeper waters would force the fisher folks to travel further from the coasts in order to increase their catch. Seaweed production, already being practiced as an adaptation to climate change in a number of poor and depressed coastal communities could also be impacted adversely.

Decreased yields and inadequate job opportunities in the agricultural sector could lead to migration and shifts in population, resulting to more pressure in already depressed urban areas, particularly in mega cities. Food security will largely be affected, especially if timely, effective and efficient interventions are not put in place. Insufficient food supply could further lead to more malnutrition, higher poverty levels, and possibly, heightened social unrest and conflict in certain areas in the country, and even among the indigenous tribes.

A careful assessment of primary and secondary impacts in this sector, particularly, in production systems and livelihoods will go a long way in avoiding food security and livelihood issues. Proactive planning (short- and long-term adaptation measures) will help in attaining poverty eradication, sufficient nutrition and secure livelihoods goals. There is a wide cross-section of adaptation strategies that could be put in place, such as horizontal and vertical diversification of crops, farmer field schools which incorporate use of weather/climate information in agricultural operations, including policy environment for subsidies and climate-friendly agricultural technologies, weather-based insurance, and others. To date, there has not been much R&D that has been done on inland and marine fisheries technologies, a research agenda on resilient marine sector could form part of long-term planning for this subsector.


Coastal Resources

The countrys coastal resources are highly vulnerable due to its extensive coastlines. Sea level rise is highly likely in a changing climate, and low-lying islands will face permanent inundation in the future. The combined effects of continued temperature increases, changes in rainfall and accelerated sea level rise, and tropical cyclone occurrences including the associated storm surges would expose coastal communities to higher levels of threat to life and property. The livelihood of these communities would also be threatened in terms of further stress to their fishing opportunities, loss of productive agricultural lands and saltwater intrusion, among others.

Impact and vulnerability assessment as well as adaptation planning for these coastal areas are of high priority. Adaptation measures range from physical structures such as sea walls where they still are cost-effective, to development/revision of land use plans using risk maps as the basis, to early warning systems for severe weather, including advisories on storm surge probabilities, as well as planning for and developing resilient livelihoods where traditional fishing/ agriculture are no longer viable.



Human health is one of the most vital sectors which will be severely affected by climate change. Incremental increases in temperatures and rain regimes could trigger a number of adverse impacts; in particular, the outbreak and spread of water-based and vector-borne diseases leading to higher morbidity and mortality; increased incidence of pulmonary illnesses among young children and cardiovascular diseases among the elderly. In addition, there could also be increased health risk from poor air quality especially in urbanized areas.

Surveillance systems and infrastructure for monitoring and prevention of epidemics could also be under severe stress when there is a confluence of circumstances. Hospitals and clinics, and evacuation centers and resettlement areas could also be severely affected under increased frequency and intensity of severe weather events.

Moreover, malnutrition is expected to become more severe with more frequent occurrences of extreme events that disrupt food supply and provision of health services. The services of the Department of Health will be severely tested unless early and periodic assessments of plausible impacts of climate change are undertaken.



Scientific assessments have indicated that the Earth is now committed to continued and faster warming unless drastic global mitigation action is put in place the soonest. The likely impacts of climate change are numerous and most could seriously hinder the realization of targets set under the Millennium Development Goals; and thus, sustainable development. Under the UNFCCC, Country Parties have common but differentiated responsibilities. All Country Parties share the common responsibility of protecting the climate system but must shoulder different responsibilities. This means that the developed countries including those whose economies are in transition (or the so-called Annex 1 Parties) have an obligation to reduce their greenhouse gas emissions based on their emissions at 1990 levels and provide assistance to developing countries (or the so-called non-Annex 1 Parties) to adapt to impacts of climate change.

In addition, the commitment to mitigate or reduce anthropogenic greenhouse gas emissions by countries which share the responsibility of having historically caused this global problem, as agreed upon in the Kyoto Protocol, is dictated by the imperative to avoid what climate scientists refer to as the climate change tipping point. Tipping point is defined as the maximum temperature increase that could happen within the century, which could lead to sudden and dramatic changes to some of the major geophysical elements of the Earth. The effects of these changes could be varied from a dramatic rise in sea levels that could flood coastal regions to widespread crop failures. But, it still is possible to avoid them with cuts in anthropogenic greenhouse gases, both in the developed and developing countries, in particular, those which are now fast approaching the emission levels seen in rich countries.

In the Philippines, there are now a number of assisted climate change adaptation programmes and projects that are being implemented. Among these are the Millennium Development Goals Fund 1656: Strengthening the Philippines’ Institutional Capacity to Adapt to Climate Change funded by the Government of Spain, the Philippine Climate Change Adaptation Project (which aims to develop the resiliency and test adaptation strategies that will develop the resiliency of farms and natural resource management to the effects of climate change) funded by the Global Environmental Facility(GEF) through the World Bank, the Adaptation to Climate Change and Conservation of Biodiversity Project and the National Framework Strategy on Climate Change (envisioned to develop the adaptation capacity of communities), both funded by the GTZ, Germany.