The effects of climate change are already a daily reality for many people, particularly for the world’s poorest and most vulnerable.

Weather is becoming more extreme and unpredictable, bringing severe storms, more floods and droughts. Glaciers, permafrost and sea ice are disappearing; sea levels are rising; forests are shrinking; water tables are falling; rivers are running dry and seasons are changing. TheWorld Health Organization has estimated that 150,000 people are dying every year because of climate change.⁹

In recent years, some of the worst droughts on record have been experienced in Africa and Australia; there have been extreme floods across South Asia, intense cyclones in Asia and the Caribbean and record heat waves.

The Intergovernmental Panel on Climate Change (IPCC) reports that, by 2020, productivity from agriculture in many African countries could be reduced by as much as 50 percent. These negative impacts on agriculture will compromise food security and increase cases of malnutrition.¹⁰

The scientific predictions are confirmed by the daily experiences of poor communities. Trócaire (Caritas Ireland) has documented anecdotal evidence from people living in resource-poor communities across the globe.¹¹ Approximately 90 percent of respondents reported significant changes in seasonal weather patterns and 95 percent reported changes in rainfall patterns. Many respondents described more erratic rainfall patterns with fewer rainy days and longer dry spells during the season, as well as the later onset and/or the early finish of the rainy season. Such trends contribute to reduced overall rainfall, which has a devastating impact on the agriculture upon which rural communities depend.

Poor farmers, fishermen, pastoralists and those largely dependent on forest products are most affected by increases in temperature and disrupted hydrological cycles, and have a limited asset base to enable them to adapt to these changes. Such challenges threaten to reverse improvements in the lives of poor people, achieved through the support of organisations such as Caritas.

Climate change compounds the poverty that persists in most developing countries. Since the 1960s, the number of victims of natural disasters has increased by an average of 900 percent. Climate change is among the principle causes that some aid agencies link to the increase in humanitarian emergencies.¹² In Kenya, the premature ending of the March-May rains in recent years has exacerbated the drought caused by several seasons of poor rainfall. In Eritrea, poor rains in 2004 caused drinking water shortages, and in southern Africa, more frequent droughts have resulted in widespread starvation and economic hardship.

It is estimated that two billion people now depend on the fragile ecosystems of arid and semi-arid areas, which are expected to experience further increases in water stress. Some 634 million people, one tenth of the global population, are living in low lying and at risk coastal areas.¹³

Caritas organisations around the world are dealing on a regular basis with the impacts of climate-related crises, which are increasing in frequency and intensity. The number of humanitarian disasters recorded has increased from around 200 to more than 400 over the past two decades and seven out of every ten disasters is now climate-related.¹⁴

Caritas Oceania reports that people in the South Pacific are losing their islands to rising sea levels. Caritas India and Caritas Peru describe how vital water will be lost as glaciers in the Himalayas and Andes recede. Caritas Myanmar and Caritas Bangladesh have been forced to respond to increasing flooding and destruction caused by typhoons.

Other national Caritas organisations speak about increasing numbers of internally displaced farmers who have become squatters in ever-expanding cities. Catholic Charities (a Caritas member in the USA) observed that those who suffered most from Hurricane Katrina in the southern United States were the poor. Caritas agencies were called to help the people of Haiti when they suffered four hurricanes in 2008.

The effects of climate change will also have an impact on patterns of population movement and settlement. This displacement will come as a result of slow-onset changes such as sea level rise and desertification, as well as rapid onset disasters such as cyclones or tsunamis. Although difficult to predict, it is estimated that by 2050, hundreds of millions of people may be displaced as a result of environmental changes.¹⁵

In areas affected by landslide, flood, cyclone or tsunami, people are typically evacuated inland as urban migrants. In these cases, the UN’s Guiding Principles for Internally Displaced Persons (IDPs) provide normative assistance and protection for these people. ¹⁶

For those in areas facing a high risk from rising sea levels, loss of territory may be permanent and may require migration across national borders. In such cases, an international law is needed to address the plight of individuals and whole communities who may be rendered stateless. In order for this to happen, a clear definition will be required for the term‘environmental migrant’.

An additional issue related to migration is the often cited link between climate change and conflict. Climate change impact may push populations to migrate to other areas in search of more secure livelihoods. The arrival of migrants may increase competition for resources and services, as well as alter the ethnic composition in host communities, resulting in tensions that escalate into violence. In order to reduce possible future conflicts, governments need to acknowledge the importance of good natural resource management and implement such measures within their national borders. Furthermore, room for dialogue needs to be enhanced between neighbouring countries so that regional programmes can be implemented.

Climate change also has a serious impact on health, compromising food security and causing more deaths and injuries as a result of storms and floods. Scarcity of water, which is essential for hygiene – as well as excess water due to more frequent and torrential rainfall – are increasing the burden of diarrhoeal disease, which is spread through contaminated food and water.

Heat waves, especially in urban centres, cause deaths and exacerbate diseases, mainly in elderly people with cardiovascular or respiratory disease. In 2003, 37,000 people who could not escape brutal heat waves died in Europe. Changing temperatures and patterns of rainfall are expected to alter the geographical distribution of insect vectors that spread such infectious diseases as malaria and dengue fever.¹⁷