Climate change and human health

Climate change is the significant and lasting changes in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It can manifest as a change in average weather conditions or in the distribution of weather events around an average condition.

It is characterized by alterations in temperature, precipitation, wind patterns, and other elements of the Earth’s climate system. The current phase of climate change is largely attributed to human activities, particularly the emission of greenhouse gases such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), which enhance the natural greenhouse effect and lead to an increase in the Earth’s surface temperature. This human-driven climate change, is referred to as global warming, and has been observed since the pre-industrial period (mid-to-late 19th century), with significant acceleration in recent decades.

Key aspects of current climate change include:

1. GLOBAL WARMING: An increase in Earth’s average surface temperature due to rising levels of greenhouse gases.
2. CHANGES IN PRECIPITATION PATTERNS: Alterations in rainfall and snowfall patterns, leading to more intense rain events in some regions and increased droughts in others.
3. MELTING ICE AND SNOW: The reduction of ice masses, including glaciers, ice caps, and polar ice sheets, contributing to rising sea levels.
4. RISING SEA LEVELS: Increased volumes of water from melting ice and the thermal expansion of seawater as it warms, leading to coastal erosion, increased flooding, and loss of habitat in coastal regions.
5. OCEAN ACIDIFICATION: Increased CO2 levels lead to higher concentrations of carbonic acid in the oceans, affecting marine ecosystems and organisms, particularly those with calcium carbonate shells or skeletons.

In today’s context, the issue requires global cooperation and concerted efforts to reduce greenhouse gas emissions, transition to renewable energy sources, and adapt to unavoidable impacts. Further, it requires a multi-faceted approach, including mitigating climate change itself, adapting health systems to better respond to climate-related health risks, improving public health infrastructure, and integrating climate considerations into public health planning and response strategies. Collaboration across sectors and disciplines, along with community engagement and education, are crucial for effectively managing the health challenges posed by climate change.

Certain groups are disproportionately affected by the health impacts of climate change, including children, the elderly, economically disadvantaged populations, indigenous communities, and people with pre-existing health conditions. These groups may have limited capacity to adapt and are more likely to experience adverse health outcomes.

Global climate change encompasses a wide array of changes to the Earth’s climate system, resulting from the increase in global average temperatures primarily due to human activities, especially the emission of greenhouse gases.

1. RISING TEMPERATURES: One of the most direct features of global climate change is the increase in global average surface temperatures. This warming is evident in the long-term trend over the past century, with recent decades being the warmest in the historical record.
2. MELTING ICE AND GLACIERS: Warming temperatures lead to the melting of ice caps, glaciers, and permafrost. This melting contributes to rising sea levels and can also release methane, a potent greenhouse gas, from thawing permafrost.
3. RISING SEA LEVELS: The expansion of seawater as it warms, combined with the addition of water from melting ice sheets and glaciers, contributes to rising sea levels. This can lead to coastal erosion, increased flooding, and the loss of coastal habitats.
4. CHANGING PRECIPITATION PATTERNS: Climate change affects precipitation patterns, leading to changes in the frequency, intensity, and duration of rainfall events. Some regions experience increased rainfall and flooding, while others face more severe droughts and water scarcity.
5. ECOSYSTEM AND BIODIVERSITY CHANGES: Climate change affects ecosystems and biodiversity, altering habitats, and putting stress on plant and animal species. This can lead to shifts in species distributions, changes in migration patterns, and the disruption of ecological relationships.
6. IMPACT ON AGRICULTURE: Changes in temperature and precipitation patterns, along with increased frequency of extreme weather events, can affect agricultural productivity. This can lead to challenges in food security, changes in crop yields, and the need for adjustments in farming practices.
7. SOCIOECONOMIC IMPACTS: The effects of climate change have significant socioeconomic implications, including impacts on economies, infrastructure, and human settlements, particularly in vulnerable communities.

Climate change has profound and diverse impacts on human health, affecting individuals and communities in several ways. These impacts can be direct, resulting from extreme weather events and changes in environmental conditions, or indirect, through disruptions to social, economic, and environmental determinants of health:

1. HEAT-RELATED ILLNESSES AND MORTALITY: Increasing temperatures and more frequent and intense heatwaves contribute to heat stress, heatstroke, and dehydration. These conditions can exacerbate cardiovascular and respiratory diseases, leading to increased morbidity and mortality, especially among vulnerable populations such as the elderly, children, and those with pre-existing health conditions.
2. AIR QUALITY AND RESPIRATORY DISEASES: Climate change can worsen air quality by increasing the concentration of pollutants and allergens, such as ground-level ozone and particulate matter from wildfires and dust storms. Poor air quality is linked to respiratory conditions, including asthma, allergic diseases, and other chronic respiratory disorders.
3. VECTOR-BORNE DISEASES: Changes in temperature, precipitation, and humidity affect the distribution, seasonality, and abundance of disease vectors like mosquitoes and ticks. This can alter the geographic range and transmission patterns of vector-borne diseases, including malaria, dengue fever, Zika virus, Lyme disease, and West Nile virus, potentially exposing new populations to these health threats.
4. WATER-RELATED ILLNESSES: Climate change impacts the availability and quality of water, leading to increased risks of waterborne diseases, especially in areas with inadequate water treatment and sanitation facilities. Flooding and heavy rainfall can contaminate water supplies with pathogens, while droughts can concentrate pollutants in water sources, leading to diseases such as cholera, giardiasis, and cryptosporidiosis.
5. FOOD SECURITY AND NUTRITION: Climate change affects food production and availability, with implications for nutrition and food security. Changes in temperature and precipitation patterns, along with extreme weather events, can reduce crop yields, affect livestock productivity, and disrupt fishing communities. This can lead to malnutrition, micronutrient deficiencies, and increased susceptibility to diseases.
6. MENTAL HEALTH AND WELL-BEING: The psychological impacts of climate change are significant, encompassing stress, anxiety, depression, and post-traumatic stress disorder (PTSD) following extreme weather events like hurricanes, floods, and wildfires. The uncertainty and perceived threats associated with climate change can also contribute to emotional distress and anxiety.
7. DISPLACEMENT AND CONFLICT: Climate change can lead to displacement and increase the risk of conflict by exacerbating resource scarcity, particularly water and food. The resulting social and economic pressures can heighten tensions within and between communities, contributing to health impacts associated with displacement, including increased exposure to infectious diseases, malnutrition, and mental health disorders.
8. VULNERABLE POPULATIONS: Certain groups are disproportionately affected by the health impacts of climate change, including children, the elderly, economically disadvantaged populations, indigenous communities, and people with pre-existing health conditions. These groups may have limited capacity to adapt and are more likely to experience adverse health outcomes.