The increase in extreme weather events is wreaking havoc around the world, and it may be damaging the health of newborns in some of the world’s most remote and vulnerable populations. New research published Monday in Nature Sustainability finds a strong link between extreme rain events in the Amazon, which have been supercharged by climate changeand worrisome risks for babies such as low birth weight and shorter pregnancies.
The study authors worked with a treasure trove of more than 291,000 digitized birth records between 2006 and 2017 from Amazonas, a state in Brazil that is almost entirely within the Amazon jungle. The data included births from one band of different socioeconomic groups in 43 different municipalities located along the rivers. (The researchers excluded major cities from their sample, but included births in both rural and urban areas.)
These birth records not only marked the birth of a baby: they also included the baby’s weight, as well as valuable information about the mother’s age, location, marital status, whether or not they were members of an indigenous group, and how much formal education they had received. Using the provided dates of birth, the researchers were able to retroactively map the mother’s pregnancy and link it to any extreme rain events during that time period.
The research found a definitive link between extreme rainfall and worrisome effects on babies, such as lower-than-average birth weight, premature births, and restricted fetal growth. Babies whose mothers experienced extreme rainfall during pregnancy had a birth weight of almost 7 ounces (200 grams) lower than average. That may not sound like much, but it is “very, very significant” for babies, said Luke Parry, one of the study’s authors.
“If you weigh less than 2.5 kilos (5.5 pounds)That has been associated with many developmental consequences later in life. “ Parry said. Even non-extreme rain events, the research found, were also correlated with lower birth weight: Babies were 40% more likely to be born underweight if their mothers were exposed to any form of increased rainfall during pregnancy. The study was not designed to explain exactly why this is happening, and it did not identify a specific scientific link between low birth weight and river flooding.
“It’s quite difficult to separate the effects of different mechanisms because they all tend to occur at the same time,” Parry said, noting that more research is needed in this region and others. But he noted that the rise in infectious diseases such as malaria or cholera, food insecurity and severe emotional stress can come with extreme rains and related flash floods in poorer river-dependent communities in the Amazon. The research also looked at how a higher income could change delivery outcomes, finding a marked difference in birth weight between the most favored and least favored mothers in the sample.
“Even without extreme prenatal exposure [weather], if a baby is born to a single indigenous adolescent mother with no formal education or birth care, the average birth weight is 648 grams (1.42 pounds) lower on average, ”Parry said. These extreme rainfall events, he said, are simply “amplifying the existing disadvantages” for the poorest populations in Brazil.
Climate change is causing “large-scale disruption to these communities,” Parry said. Recent research has shown that the flooding in the region has increased fivefold. While part of it has been driven by natural cycles such as El Niño, CClimate change is also increasing the likelihood of heavy downpours around the world due to the simple fact that a warmer atmosphere can hold more water. Despite this, Parry said, there has been relatively little research on how the lives and health of those who actually live in the Amazon are affected.
“These remote populations are often out of the political consciousness of the rest of Brazilian society and legislators,” Parry said. “Tthere is a lot of physical research here on the effects of climate change in the Amazon … but the true Amazonians who have contributed very little to climate change are the most affected and basically forget about them. ”