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Study warns of health risks of climate changes


Julia Dias


Climate changes are the major health concern of the 21st century. The increased global temperature is already felt in current heat waves, vector-borne diseases and in the food security of populations around the globe. Twenty-seven academic institutions of all continents, including Fiocruz, have just published the Lancet Countdown report to monitor this.

The report, which exists since 2016 and gathers 41 indicators, warns of risks health systems around the world will face if governments and society don’t act fast to curb global warming. 

“Until recently, health impacts were little studied on this field, but it’s all about health,” explains Sandra Hacon, researcher at the National School of Public Health Sérgio Arouca (Ensp/Fiocruz) and participant of the study.

Small changes in temperature and rainfalls may have a great impact in the transmission of vector-borne and waterborne diseases. According to the report, in 2016, the overall vector capacity for dengue virus transmission was the highest ever recorded, increasing by 9.1% for Aedes aegypti and 11.1% for Aedes albopictus, from the 1950 baseline.

Cholera and malaria also registered increases associated with climate change. In 2016, the Baltic coastal region had a 24% increase in Vibrio cholerae transmission capacity compared to 1980, and Sub-Saharan Africa's plateaus registered a 27% increase in malaria transmission capacity compared to 1950.

Vulnerability to heat extremes has also increased steadily since 1990 in all regions. In 2017, 157 million more people than in 2000 were exposed to heat wave events, an increase of 18 million people compared to 2016. These waves are associated to increased rates of heat stress, sunstroke, heart failure, and acute kidney damage from dehydration. Elderly and people working outdoors, such as farmers and civil construction workers, are more vulnerable to such conditions.

“Trends in impacts, exposures and vulnerabilities of climate change show an unacceptably high level of risk to the current and future health of populations around the world,” warns the document published by the leading European medical journal, The Lancet, on November 28, with the participation of the World Bank and the World Health Organization (WHO).

“The Lancet Countdown is an essential partner for progress in the achievement of the Paris Agreement goals, the most important health treaty in the century,” declared WHO Director-General, Tedros Adhanom Ghebreyesus.

Climate change impacts are also felt in national economies and family budgets. According to the publication, 153 billion hours of work were lost in 2017 because of the heat, more than 62 billion hours of increase since 2000. In 2017, 712 extrema climate events resulted in USD 326 billion in economy losses, almost three times more the total loss in 2016.

Food security is another field affected by climate change with a decline in crop yields in all regions of the world.

“We can’t wait to act, we must be proactive. Economic and health losses are very high if we wait for disasters to happen,” declares the Fiocruz researcher. Globally, expenses to adapt to climate changes remain well below the USD 100 billion per year commitment made under the Paris Agreement.

The world still needs to effectively reduce its gas emissions. The speed of climate change threatens our lives and the lives of our children. Following the current trends, we have exhausted the carbon supply necessary to keep warming below 2 by 2ºC by 2032. Climate changes impacts on health above this level threaten to overwhelm our emergency and health services,” declares the Lancet Countdown co-chair and former WHO director, Anthony Costello. 

Recommendations for Brazil

Specific recommendations were made for some countries, including Brazil, with the global report. In addition to Fiocruz, the National Institute for Space Research (Inpe) and the Brazilian Society of Family and Community Medicine (SBMFC) participated in the Brazilian collaboration.

While heat waves are a major concern in Europe, where aging populations make it more vulnerable to such events, South America and Southeast Asia tend to be more affected by floods and droughts. Annual flood frequencies and extreme temperature events are increasing since 1990. Changing flows may cause changes in ecosystems and lead to the emergence of new diseases, and also changes the incidence of vector diseases already known.

For Sandra, however, risks also raise possibilities, as the scientific progress. She emphasizes the role Brazilian scientists and institutions play in this field. “Brazil is leading studies on climate change, we are ahead of Latin America in this field, in areas such health, water resources and agriculture. We have the Amazon, which is a natural laboratory. The Amazon is a treasure not only for Brazil, but for the world.”

Experiences of low-carbon economies in the Amazon and the Cerrado show that sustainable development is an opportunity to solve poverty as well. “Unfortunately, we can’t show these experiences to the world. It’s sad that Brazil decided not to host COP 25 as it would be a space for the country to reaffirm its leadership in this field,” declares Sandra.

Although the Lancet Countdown does not include an indicator on the effects of deforestation on health, the document for Brazil includes a case study on the Amazon illustrating the interrelationship between global changes and microclimate changes. Estimates suggest the Amazon will be most affected by increased temperature compared to other regions of Brazil.

In addition, burning and deforestation are already a major cause of illness in the region. The burning season is associated with the birth of underweight children and increased hospital admissions and respiratory diseases, especially in children and the elderly.

Deforestation in the Amazon is currently ranging from 15 to 17%, close to the inflection point of 20 to 25%, which some authors state as irreversible in the savannization of most of the forest. Such data not only increases gas emissions in the country, but also harms new scientific discoveries by destroying the unique biodiversity of the forest.

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