Malaria and dengue fever will spread to reach billions of people if greenhouse gas emissions continue to rise unabated, a new study says. More than 8 billion people could be at risk of malaria and dengue fever by 2080.
The figures are based on projections of a population growth of about 4.5 billion over the same period, and a temperature rise of about 3.7C by 2100 as researchers predict that up to 4.7 billion more people could be threatened by the world’s two most prominent mosquito-borne diseases, compared with 1970-99 figures.
The London School of Hygiene & Tropical Medicine (LSHTM) and published in the Lancet Planetary Health journal, found that if emission levels continue to rise at current rates, the effect on global temperatures could lengthen transmission seasons by more than a month for malaria and four months for dengue over the next 50 years.
Malaria kills more than 400,000 people every year, mostly children. In 2019, more than 90% of an estimated 230m cases occurred in Africa. Currently, artemisinin-based combination therapy is the best available treatment for the most dangerous form of malaria, P falciparum, which accounts for 90% of cases. Dengue has no specific treatment. The disease is under-reported, with almost half the world’s population at risk. Dengue is estimated to infect 100 million to 400 million people every year, killing 20,000.
5 million people die each year globally because of excessively hot or cold conditions, a 20-year study has found – and heat-related deaths are on the rise. The study involving dozens of scientists around the world found that 9.4% of global deaths each year are attributable to heat or cold exposure, equivalent to 74 extra deaths per 100,000 people.
Greenhouse gas emissions and land use change are a key factor in extreme precipitation events such as flooding and landslides around the world, a study has found. In recent years, there have been numerous instances of flooding and landslides: extreme precipitation, an amount of rainfall or snowfall that exceeds what is normal for a given region, can be a cause of such events.
While there are regional differences, and some places are becoming drier, Met Office data shows that overall, intense rainfall is increasing globally, meaning the rainiest days of the year are getting wetter. Changes to rainfall extremes – the number of very heavy rainfall days – are also a problem. These short, intense periods of rainfall can lead to flash flooding, with devastating impacts on infrastructure and the environment.
“We are already observing a 1.2C warming compared to pre-industrial levels,” pointed out Dr Sihan Li, a senior research associate at the University of Oxford, who was not involved in the study. She said: “If warming continues to increase, we will get more intense episodes of extreme precipitation, but also extreme drought events as well.”
Climate crisis ‘may put 8bn at risk of malaria and dengue’ | Global development | The Guardian
Human activity influencing global rainfall, study finds | Climate change | The Guardian
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