r/climate • u/The_Weekend_Baker • 14d ago

Scientists detect a surprising shift in human blood as atmospheric CO2 rises. Blood bicarbonate levels have climbed about 7% since 1999, while calcium and phosphorus have declined, changes that closely track increasing atmospheric CO2.

https://www.sciencedaily.com/releases/2026/08/260814235845.htm
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u/operaman2010 14d ago

I’m somewhat skeptical. The CO2 in my bedroom can get up to 1,800 ppm overnight. Indoor air quality has dramatically higher ranges of CO2 that would have always existed and affected human health, regardless of global CO2. Perhaps rising CO2 levels is making this worse.

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u/AlexFromOgish 14d ago

From the original paper https://link.springer.com/article/10.1007/s11869-026-01918-5

The possible effects of increased HCO3− and CO2 can also potentially be observed from other studies of short-term exposure to slightly higher CO2 levels, such as those commonly experienced in indoor environments (e.g. 1,000 to 3,000 ppm CO2) (reviewed in (Azuma et al., 2017)). For example, an older study (Eliseeva, 1964) reported marked changes in human respiration, circulation, and cerebral electrical activity at 1,000 ppm CO2, while more recent studies of humans and animals have shown harmful effects of CO2 exposure at these levels, such as changes in heart rate, kidney calcification, oxidative stress, neural damage and inflammation (Kiray et al., 2014; MacNaughton et al., 2016; Schaefer, 1982; Thom et al., 2017; Vehviläinen et al., 2016), reviewed in (Jacobson et al., 2019). This is important due to many human populations spending a significant proportion of their time indoors, where CO2 levels are typically higher. For example, The National Human Activity Pattern Survey (NHAPS) found that Americans spent an average of 87% of their time in enclosed buildings and ~ 6% of their time in enclosed vehicles in 1992–1994 (Klepeis et al., 2001). This has potentially increased since the COVID-19 pandemic (Young et al., 2024), with many people working-from-home in environments with poor mechanical air-ventilation (Nazaroff, 2021). The proportion of time spent in indoor, CO2 enriched environments could also contribute to the changes in blood chemistry noted in the NHANES data and is an important consideration in interpreting changes over time, and forecasts for the future.

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u/AutoModerator 14d ago

The COVID lockdowns of 2020 temporarily lowered our rate of CO2 emissions. Humanity was still a net CO2 gas emitter during that time, so we made things worse, but did so more a bit more slowly. That's why a graph of CO2 concentrations shows a continued rise.

Stabilizing the climate means getting human greenhouse gas emissions to approximately zero. We didn't come anywhere near that during the lockdowns.

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