A steady drumbeat of new research on climate change is making clear that while the worst consequences of rising global temperatures may still be years away, the crisis caused by man-made greenhouse gas emissions has already begun.
For years, climate change deniers cast doubt on what they regarded as “doom and gloom” global warming predictions, arguing that forecasting future changes based on an increase in the concentration of carbon dioxide in the earth’s atmosphere was little more than idle speculation. But with each passing year, global average temperatures have continued to climb, in tandem with carbon dioxide levels measured on the so-called Keeling Curve.
Along the way, another disconcerting reality has come into view: The effects of climate change that were long predicted by scientists are now being witnessed and confirmed by multiple peer-reviewed studies.
The following research is just a fraction of the studies that have emerged in the past year alone that make clear that combating climate change promises to be the single biggest challenge facing humankind in the years to come.
Dwindling oxygen levels in lakes threaten species
A study published Wednesday in the journal Nature by researchers at Rensselaer Polytechnic Institute and the University of Minnesota has found that, because of rising temperatures, oxygen levels in lakes around the world have plummeted.
“We find deep-water lake habitats are especially threatened, and deep-water DO [deoxygenation] trends may portend future losses of cold-water and oxygen-sensitive species, increased internal nutrient loading, which exacerbates eutrophication and the formation of harmful algal blooms, and potentially increased storage and subsequent outgassing of methane,” said the study.
Since 1980, the study found, oxygen levels at the surface of freshwater lakes have dropped 5.5 percent, and 18.6 percent in deeper water.
More than one-third of all deaths from heat are attributable to climate change
A study published this week in Nature Climate Change in which researchers from several universities used data collected from 43 countries concluded that 37 percent of heat-related deaths between 1991 and 2018 can be attributed to climate change.
“We can already measure negative impacts on health, in addition to the known environmental and ecological effects,” Antonio Gasparrini, a professor of biostatistics and epidemiology at the London School of Hygiene and Tropical Medicine and one of the study’s senior authors, told the news agency AFP.
The study said that the number of people in the U.S. who die annually from heat death caused by climate change is approximately 1,100.
In Maricopa County, Ariz., officials recorded this year’s first heat death on Tuesday. In 2020, the county, which includes Phoenix, set a record high for heat deaths at 323. That figure represents an increase of 62 percent from 2019, the second-highest year for heat deaths on record in the county.
Wildfires are getting worse
Numerous studies have concluded that warmer temperatures are worsening wildfires in several areas of the world. Research published in September found increased risk of wildfires in the “western U.S. and Canada, southern Europe, Scandinavia and Amazonia,” due in part to drier vegetation resulting from higher global temperatures.
“In terms of the trends we’re seeing, in terms of the extent of wildfires, and which have increased eight to ten-fold in the past four decades, that trend is driven by climate change,” lead researcher Matthew Jones of the University of East Anglia in Norwich, England, told the BBC.
The study also made clear that raking forests, as former President Donald Trump suggested as a way to prevent wildfires, was not in and of itself a solution.
“Human-induced climate change promotes the conditions on which wildfires depend, enhancing their likelihood and challenging suppression efforts,” the study said.
A draft of a separate report by the National Park Service obtained by the Visalia Times Delta found that 10 percent of the giant sequoia population in Northern California was destroyed in the 2020 Castle Fire. Redwood forests are desperately needed to help remove carbon dioxide from the atmosphere. A single redwood, research has shown, can absorb as much carbon as 250 trees of an average species.
Data on the extent of the effect of wildfire smoke on human health is still emerging. A study published in January in the Proceedings of the National Academy of Sciences found that wildfire smoke accounted for up to half of all health-damaging small-particle pollution in the western U.S. in recent years. The study also concluded that climate change had made wildfires more destructive.
“From a climate perspective, wildfires should be the first things on our minds for many of us in the U.S.,” said Marshall Burke, an associate professor of earth system science at Stanford University and the lead author of the study.
“Most people do not see sea-level rise. Most people do not ever see hurricanes. Many, many people will see wildfire smoke from climate change,” Burke added.
Glaciers are melting
A study published in April in the journal Nature found that the majority of the world’s glaciers were melting faster thanks to climate change. As a result, roughly 328 billion tons of meltwater was being added to the world's oceans each year.
Of particular concern is the massive Thwaites Glacier in Antarctica, the collapse of which, scientists warn, could destabilize other glaciers, resulting in up to 11 feet of global sea-level rise. A second study published in April found that the Thwaites, whose nickname is the “Doomsday Glacier,” has been melting faster than previously suspected due to the flow of warm water beneath it.
“Our observations show warm water impinging from all sides on pinning points critical to ice-shelf stability, a scenario that may lead to unpinning and retreat,” the authors of the study wrote.
While annual sea-level rise continues to be measured in millimeters, the trend line is going in a worrisome direction. Already, coastal communities in the U.S. have been forced to make hard choices about relocating residents or building extensive barriers to try to keep the ocean from encroaching further. Should the deterioration of the Thwaites Glacier continue, those responses would quickly become inadequate.
Storms and hurricanes are becoming more frequent and costly
According to the National Oceanic and Atmospheric Administration (NOAA), the frequency and damage costs of major weather events have been increasing as global temperatures continue to rise.
“2020 set a new record for events, with 22 billion-dollar weather and climate disasters — shattering the previous annual record of 16 events in 2011 and 2017. 2020 was the sixth consecutive year in which 10 or more billion-dollar disaster events occurred in the U.S.,” NOAA states on its website. “There were 13 severe storms, seven tropical cyclones, one drought, and one wildfire event in 2020, for a total cost of $95 billion. These events resulted in the deaths of 262 people.”
A study published in May by Nature Communications found that $8 billion in damages during Hurricane Sandy in 2012 was attributable to an increased storm surge that resulted from climate change.
In March, the reinsurance firm Swiss Re Institute released a report detailing the mounting economic costs of the climate crisis.
“2020 will be remembered for the global health and economic crisis triggered by the COVID-19 pandemic. But while COVID-19 was a stress test for society and the economy, it has an expiry date — climate change does not,” Jérôme Haegeli, Swiss Re Group chief economist, told Insurance Business America.
He continued: “In fact, climate change is already becoming visible in more frequent occurrences of secondary perils such as flash floods, droughts and forest fires. Natural disaster risks are increasing, and climate change will significantly exacerbate them. This underlines the urgency to better protect our communities against catastrophic losses while dramatically reducing carbon emissions. Unless mitigating measures are taken, such as greening the global economic recovery, the cost to society will increase in the future.”
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