One of the most disturbing conclusions of the latest “Intergovernmental Panel on Climate Change” report is the permanence of climate impacts. Changes like shrinking ice sheets, rising sea levels and oxygen depletion and acidification of the oceans are deemed “irreversible for centuries to millennia.”
An April 19 article in Carbon Brief, “Climate change could cause ‘irreversible impacts’ to lake ecosystems,” illustrates that the Midwest is unlikely to evade the irremediable damage brought about by global warming. The article discusses the increased stratification of northern hemisphere lakes as temperatures warm and the harm this will likely produce as fish are deprived of oxygen in cooler, deeper waters. Stratification is the layering of lakes by temperature, which can prevent surface oxygen from mixing with other layers.
According to a study in Nature Communications reviewed in this piece, the Great Lakes are particularly vulnerable and “are already experiencing ‘rapid changes’ in their stratification periods.” Some lake ecosystems could undergo “catastrophic changes” under high emissions scenarios.
To quote lead author Dr. Richard Woolway: “Fish often migrate to deeper waters during the summer to escape warmer conditions at the surface – for example during a lake heatwave. A decrease in oxygen at depth will mean that fish will have no thermal refuge, as they often can’t survive when oxygen concentrations are too low.”
On June 30, 49 U.S. scientific organizations, including the American Association for the Advancement of Science and the American Meteorological Society, sent a letter to Congress expressing the “urgency of boldly addressing climate change.” The letter asserts: “Rapid action is necessary to avoid potentially disastrous consequences for health, biodiversity, food security, water availability, and national security.”
A $3.5 trillion reconciliation bill is now being considered in Congress, and it’s likely to contain major climate provisions. Congress may have a narrow window for substantive climate action. Please call your representatives in Washington and urge them to include a price on carbon dioxide emissions in this legislation. According to the IPCC, “Explicit carbon prices remain a necessary condition of ambitious climate policies.” It’s the single most powerful way to reduce emissions.
Hales Corners, Wisconsin