April 2019, EcoWatch
It Will Take 10 Million Years to Recover From This Man-Made Apocalypse, Guest Contributor Apr. 17, 2019 SCIENCE
By Jordan Davidson
The climate crisis has us spiraling towards higher temperatures while also knocking out marine life and insect species at an alarming rate that continues to accelerate. But, just how long will it take Earth to recover? A new study offers a sobering answer: millions of years.
The researchers tried to answer how long it takes biodiversity to recover following a mass extinction. Their paper, published in Nature Ecology and Evolution, looked at the fossil records of plankton which existed for nearly 20-million years near the last mass extinction, which killed off most dinosaurs and 80-percent of Earth’s animals, nearly 66 million years ago. Species diversity recovered after 10 million years, Newsweek reported.
“From this study, it’s reasonable to infer that it’s going to take an extremely long time — millions of years — to recover from the extinction that we’re causing through climate change and other methods,” said study co-author Dr. Andrew Fraass to Newsweek. “It is an apt warning about the time it takes to recover from massive losses in species.”
The findings have striking implications for the long-term health of the planet and the future of humanity as we confront a climate crisis, habitat destruction and invasive species, all of which parallels ancient times, according to a University of Bristol press release.
“This should serve as an important reminder: some ecological niches lost due to anthropogenic climate change will never reappear,” the authors wrote in their study. Essentially, the Earth will be drastically different after a mass extinction, according to Forbes.
The study complements other recent studies that have found declining plant and animal populations as a threat to the global food chain. Earlier this year, a separate study published in Biological Conservation found insect populations declining so rapidly that 40 percent of insect species threatened with extinction.
“The repercussions this will have for the planet’s ecosystems are catastrophic to say the least, as insects are at the structural and functional base of many of the world’s ecosystems since their rise at the end of the Devonian period, almost 400 million years ago,” the study authors wrote.
The authors of the insect study chose their words carefully to stress the importance of insects to all life on the planet.
“We only use the word “catastrophic” once, and we use it very carefully,” said study co-author Francisco Sanchez-Bayo of the University of Sydney to Civil Eats. “We chose that word deliberately: If 30 percent of insects, the largest group of animals on Earth, are in danger, that is catastrophic. Damage from a tropical cyclone can be characterized as catastrophic, but that is localized. This is global. This is a true catastrophe.”
- Human-caused extinctions have set mammals back millions of years ›
- Earth Could Take 10 Million Years to Recover From Mass Extinction … ›
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Mass Extinction, EcoWatch, Sept 2019
Some two billion years ago, a significant decline of once-abundant oxygen killed as much as 99 percent of all life on Earth in a mass extinction event larger than the one responsible for the dinosaur die-off.
Publishing their work in Proceedings of the National Academy of Sciences, a team of researchers describe the catalyst of the Great Oxidation Event (GOE) that occurred between 2.05 and 2.4 billion years ago. In the years leading up to the GOE, oxygen levels in the Earth’s atmosphere had increased significantly, resulting in the multiplication of ancient minuscule microorganisms. Suddenly, oxygen levels plummeted in what soon became one of the “most transformative events in all of Earth’s history,” shifting from “feast” to “famine” conditions that followed in the next 1 billion years, paving the way for complex life as we know it today.
“We were very surprised,” co-author Peter Crockford, a postdoctoral researcher at the Weizmann Institute of Science and Princeton University told Newsweek. “We didn’t expect to see such a large signal, nor did we expect to find it in this specific type of sample.
“Over the 100 to 200 million years before this die-off event there was a large amount of life on the planet, but after this event a huge portion died off,” said Crockford. “However, instead of recovering like more recent mass extinctions, the amount of life on the planet or size of the biosphere stayed small for the following billion years of Earth’s history—about two billion to one billion years ago.”
But how or why that shift occurred has long been contested — until now.
Barite crystals in the Costello Formation in Canada. Malcolm Hodgskiss
Scientists turned to barite, a sulfate mineral found in the Belcher Islands in Canada’s Hudson Bay that shows the geological record of oxygen in the atmosphere. An analysis of isotope geochemistry found negative values that occurred shortly after the GEO, implying a collapse in primary productivity that triggered a shift in the availability of nutrients like phosphorus. Altogether, this caused an enormous drop in life perhaps due to a decrease in oxygen levels.
“The fact that this geochemical signature was preserved was very surprising,” said study co-author Malcolm Hodgskiss. “What was especially unusual about these barites is that they clearly had a complex history.”
The increase of life in correlation with atmospheric oxygen confirms a theory known as “oxygen overshoot” whereby photosynthesis from ancient microorganisms and the natural weathering processes of rocks resulted in an increase of oxygen in the atmosphere. Oxygen-emitting organisms eventually exhausted their nutrient supply in the ocean, resulting in declining populations in a world much different than how we know it today, where a stable atmosphere balances oxygen production with consumption.
The findings shed light into ancient processes that eventually resulted in Earth as we know it today. By further studying how Earth behaves throughout time, scientists say they can better understand how atmospheres operate on planets outside of our solar system, specifically the interlink between the biosphere (where organisms live) and how that relates to levels of oxygen and carbon dioxide in the atmosphere.
“Some of these oxygen estimates likely require too many microorganisms living in the ocean in Earth’s past,” said Crockford. “So, we can now start to narrow in on what the composition of the atmosphere could have been through this biological angle.”
- It Will Take 10 Million Years to Recover From This Man-Made … ›
- Humans Are Wiping Out Species So Fast That Evolution Can’t Keep … ›
- Earth Is Facing Most Severe Extinction Crisis in 65 Million Years … ›
- The Great Oxygenation Event: The Earth’s first mass extinction. ›
- Two Billion Years Ago, up to 99 Percent of Life on Earth Died in an … ›
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2018 UNESOC-IOC’s Global Ocean Oxygen Network and other scientists call for urgent efforts to address deoxygenation in the world’s oceans in the ‘Kiel Declaration’.
The Declaration cautions that the Paris Agreement on climate change and the 2030 Agenda are “severely threatened by ocean deoxygenation”.
7 September 2018: Over 300 scientists from 33 countries issued a declaration calling for more marine and climate protection in order to urgently tackle the decline of oxygen in the world’s oceans. The scientists urge increased international efforts to enhance global awareness of oxygen depletion, immediate and decisive action to limit marine pollution and decisive climate change mitigation actions to limit global warming.
The scientists convened in Kiel, Germany, for a conference on the theme, ‘Climate and Biogeochemical Interactions in the Tropical Ocean,’ organized by the Global Ocean Oxygen Network (GO2NE), an expert group established in 2016 under UN Educational, Scientific and Cultural Organization’s Intergovernmental Oceanographic Commission (UNESCO-IOC) and the Collaborative Research Centre 754 (SFB 754). The conference took place from 3-7 September.
According to UNESCO-IOC, oxygen has decreased by two percent in the world’s oceans over the past 50 years, and the volume of oxygen-depleted water has grown fourfold. The reasons for this deoxygenation include increasing global warming and over-fertilization of the oceans, which leads to algae blooms and increased depletion of oxygen through biomass degradation. These changes are further expected to change feedbacks in the atmosphere as greenhouse gases (GHGs), including methane and nitrous oxide, form in the oxygen-free water.
The reasons for ocean deoxygenation include increasing global warming and over-fertilization of the oceans.
The ‘Kiel Declaration’ states that oxygen in the ocean “supports the largest ecosystems on the planet,” and expresses alarm that the ocean is losing oxygen, primarily as a result of GHG emissions and pollution by nutrients and organic waste. The Declaration recognizes that both the Paris Agreement on climate change and the 2030 Agenda for Sustainable Development “demand conservation and sustainable use of the ocean, seas and marine resources,” but stresses that these aims are “severely threatened by ocean deoxygenation.”
The Declaration calls on the UN, all countries, scientists and others to: raise global awareness about ocean deoxygenation through global, regional and local efforts, including interdisciplinary research and ocean education; take immediate and decisive action to limit pollution, particularly excessive nutrient input; and limit global warming through decisive climate change mitigation actions. The Declaration describes increases in deoxygenation over time, and provides evidence on how global warming impacts ocean oxygen and how deoxygenation disrupts marine ecosystems, affects fish stocks and leads to loss of biodiversity and habitats, among other evidence. [Kiel Declaration] [UNESCO-IOC Press Release]
