What Is Climate Change?

Climate change is defined as long-term and large-scale shifts in weather patterns and average temperatures. Although shifts like these can occur naturally, as the result of volcanic activity or changes in the Sun, human activities over the last 200 years have had significant effects. This has mainly been due to the burning of fossil fuels like coal, gas, and oil. As a result, the Earth is now about 1.1 °C warmer than it was 100–150 years ago, and the last decade (2011–2022) was the warmest on record. This is causing environmental effects such as rising sea levels, intense droughts, scarcity of water, and declining biodiversity (the variety of living organisms), which makes climate change an economic issue because it affects the availability of food and other resources.

How Does Climate Change Affect Our Health?

Climate change can affect human health in many ways. It can affect mental health through increased stress and anxiety, and extreme weather events can cause significant trauma. Rising sea levels and increased frequency of flooding can lead to people being displaced and increase the likelihood of water supplies becoming contaminated, which increases the spread of disease. Increasing droughts can decrease food production and the supply of water, and a warming climate also affects numbers of biting insects, such as ticks and mosquitos (both can spread disease), particularly in areas where numbers of these insects had previously been low. Extreme climate events such as heatwaves have also become more common and are lasting longer, placing a heavy burden on health systems.

What Are the Health Effects of Heatwaves?

Heatwaves are known to cause increases in death rates and the numbers of people needing medical care. During a heatwave in Europe in 2003, more than 70,000 excess deaths (the number of deaths that was above the number expected over that time period) were reported. Excess heat increases pressure on the heart, lungs, and brain, increasing the risk of death from respiratory (relating to the breathing system), cerebrovascular (relating to the brain and its blood vessels), or cardiovascular (relating to the heart and blood vessels) problems.

Who Is Most at Risk during a Heatwave?

People with pre-existing health conditions, especially cardiovascular and respiratory diseases, and the elderly are particularly at risk. Over the last 20 years, the rate of elderly people dying from heat-related causes has increased significantly. Children under 1 year of age are likely to be affected by the effects of heat and dehydration, as are people who do manual work outdoors, for whom an increased risk of chronic kidney disease has also been reported. There is also evidence that people living alone, living in areas that are more socioeconomically disadvantaged (this is defined as less access to or control over economic, social, or material resources and opportunities), or living in urban environments such as city centers are at increased risk.

What Did This Study Investigate?

To be able to deal with the challenges that heatwaves cause, healthcare systems need to be able to develop plans that will ensure that those most at risk can access the support they need during a heatwave. Advances in geographic information systems have been shown to be useful in mapping how diseases are distributed and identifying any clusters or trends. They can also take into account environmental and socioeconomic factors when analyzing data, and the availability of medical facilities. This area of research is termed “geomedicine”.

What Is Geomedicine and How Can It Improve Health Outcomes?

Geomedicine is based on the idea that good health does not come by accident. Instead, factors in our environment have an effect on our health, which means that the places where we live and work now and in the past affect our health status. By linking a person’s health status to geographic factors, such as a person’s address, geomedicine can provide health data that can help medical teams make diagnoses and better assess risk.

What Did the Authors Investigate?

In this study, the authors used an approach called “geocoding” to investigate how the scale of geographic information used in geomedical analysis affects the results. Geocoding involves defining a set of geographic coordinates, usually based on latitude and longitude, that correspond to a location. The authors argue that analyzing data by geocodes, which can specify a particular street, rather than by larger areas such as a parishes or districts provides more accurate information about public health in those areas. This means that local authorities can prioritize resources to areas with greater need.

In their study, the authors analyzed data concerning heat-related deaths among elderly people in Portugal, which were linked to cardiorespiratory problems, between 2014 and 2017. Each record included information about the house number, post code, and location of the person that died, which enabled it to be geocoded. Once geocoded, the data were generalized to the neighborhood level to protect the confidentiality of the people’s data that were included.

The results showed that some neighborhoods with low cardiorespiratory death rates were located within parishes with high rates, while conversely, neighborhoods with high death rates were located within parishes with low rates. The authors therefore stress the importance of carrying out analyses at several different scales, and note that analysis by smaller administrative areas is preferable. Just as personalized medicine has the potential to revolutionize health, so does analyzing data by individual neighborhoods.

However, the authors also note the need for authorities to develop multisector responses to the challenges that climate change brings to “keep vulnerability to a minimum and increase the resilience of healthcare and urban planning”. By improving health information systems, it is possible that the accuracy of health outcome monitoring, spatial planning in urban areas, and the management of health resources may be improved.