New record: Atmospheric carbon dioxide levels continue to rise
Scientists from NOAA and Scripps Institution of Oceanography at the University of California San Diego reported that carbon dioxide levels measured at NOAA’s Mauna Loa Atmospheric Baseline Observatory reached a peak of 424 parts per million in May. This marks a continuation of the upward trend, taking us into territory that hasn’t been witnessed for millions of years.
NOAA’s Global Monitoring Laboratory collected data on carbon dioxide (CO2) levels, revealing an average of 424.0 parts per million in May. This is the month when CO2 levels typically reach their highest point in the Northern Hemisphere. Compared to May 2022, there was an increase of 3.0 parts per million, making it the fourth-largest annual increase recorded by NOAA’s Keeling Curve. Scripps, an institution maintaining an independent record, also calculated a May monthly average of 423.78 parts per million, showing the same 3.0 parts per million increase compared to their average from May 2022.
This year, NOAA’s data were gathered from a temporary sampling site atop the nearby Mauna Kea volcano.
Carbon dioxide levels are now more than 50% higher than they were before the onset of the industrial era. “Every year we see carbon dioxide levels in our atmosphere increase as a direct result of human activity,” said NOAA Administrator Rick Spinrad, Ph.D. “Every year, we see the impacts of climate change in the heat waves, droughts, flooding, wildfires and storms happening all around us. While we will have to adapt to the climate impacts we cannot avoid, we must expend every effort to slash carbon pollution and safeguard this planet and the life that calls it home.”
CO2 is a greenhouse gas that captures and retains heat emitted from the Earth’s surface. This prevents the heat from escaping into space, resulting in an intensification of extreme weather events.
The Earth’s climate system has 16 critical tipping points that govern the safe space for humanity. Among these tipping points, nine are located in the polar regions. These are all reactive to rising emissions and temperatures. It is projected that five Arctic tipping points will be tipped when global temperatures reach +1.5°C to +2°C (Armstrong McKay et al 2022).
Arctic sea ice plays a crucial role in maintaining a cooler global climate by reflecting a significant portion of the sun’s energy back into space. However, as the planet warms and more ice melts, the Arctic Ocean is able to absorb more solar energy, thereby causing further ice loss (a key feedback loop). The power of the Arctic snow and ice to moderate global temperatures is such that, without it, scientists estimate global warming will intensify by 25-40%.
There are other critical changes in the Arctic as well, such as the rapid acidification of the ocean, which is happening four times more rapidly than in other global oceans. The loss of sea ice is promoting the uptake of atmospheric carbon dioxide by the ocean, making the water more acidic. This acidification has drastic implications for all marine life, including the phytoplankton and zooplankton at the base of the entire global good chain.
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Image source: UCSandiego and Scripps Instituion of Oceanography