Breaching a ‘carbon threshold’ could lead to mass extinction

Breaching a ‘carbon threshold’ could lead to mass extinction

SOURCE: Phys.org and MIT DATE: July 8, 2019 SNIP: Daniel Rothman, professor of geophysics and co-director of the Lorenz Center in MIT’s Department of Earth, Atmospheric and Planetary Sciences, has found that when the rate at which carbon dioxide enters the oceans pushes past a certain threshold—whether as the result of a sudden burst or a slow, steady influx—the Earth may respond with a runaway cascade of chemical feedbacks, leading to extreme ocean acidification that dramatically amplifies the effects of the original trigger. This global reflex causes huge changes in the amount of carbon contained in the Earth’s oceans, and geologists can see evidence of these changes in layers of sediments preserved over hundreds of millions of years. Rothman looked through these geologic records and observed that over the last 540 million years, the ocean’s store of carbon changed abruptly, then recovered, dozens of times in a fashion similar to the abrupt nature of a neuron spike. This “excitation” of the carbon cycle occurred most dramatically near the time of four of the five great mass extinctions in Earth’s history. Scientists have attributed various triggers to these events, and they have assumed that the changes in ocean carbon that followed were proportional to the initial trigger—for instance, the smaller the trigger, the smaller the environmental fallout. But Rothman says that’s not the case. It didn’t matter what initially caused the events; for roughly half the disruptions in his database, once they were set in motion, the rate at which carbon increased was essentially the same. Their characteristic rate is likely a property of the carbon cycle itself—not the triggers,...
Latest data shows steep rises in CO2 for seventh year

Latest data shows steep rises in CO2 for seventh year

SOURCE: The Guardian DATE: June 4, 2019 SNIP: The concentration of carbon dioxide in the atmosphere has increased by the second highest annual rise in the past six decades, according to new data. Atmospheric concentrations of the greenhouse gas were 414.8 parts per million in May, which was 3.5ppm higher than the same time last year, according to readings from the Mauna Loa observatory in Hawaii, where carbon dioxide has been monitored continuously since 1958. Scientists have warned for more than a decade that concentrations of more than 450ppm risk triggering extreme weather events and temperature rises as high as 2C, beyond which the effects of global heating are likely to become catastrophic and irreversible. This is the seventh consecutive year in which steep increases in ppm have been recorded, well above the previous average, and the fifth year since the 400ppm threshold was breached in 2014. In 2016, the highest annual jump in the series so far was recorded, from 404.1 in 2015 to 407.66 in...
It’s Official: Atmospheric CO2 Just Exceeded 415 ppm For The First Time in Human History

It’s Official: Atmospheric CO2 Just Exceeded 415 ppm For The First Time in Human History

SOURCE: Science Alert DATE: May 13, 2019 SNIP: Yet another alarming milestone of humanity’s damaging effect on the environment has now officially been reached – crossing a barrier into a hot, polluted future like the planet hasn’t witnessed in millions of years. This weekend, sensors in Hawaii recorded Earth’s atmospheric concentration of carbon dioxide (CO2) passing 415 parts per million (ppm) for the first time since before the ancient dawn of humanity. On Saturday, CO2 concentration recorded at the Mauna Loa Observatory in Hawaii by researchers from the Scripps Institution of Oceanography hit 415.26 ppm – the latest in a dire series of climatic thresholds being breached by a human society that refuses to relinquish the conveniences afforded by fossil fuels. Obviously, crossing 400 ppm was a huge symbolic moment, numerically at least, but the symbolism doesn’t end there. If carbon pollution keeps getting thicker in our atmosphere, more and more heat will become trapped on Earth, which will make the future of global warming look like something out of the planet’s distant, steamy past hundreds of millions of years ago. The last time Earth scaled such dangerous heights (and heats), there were trees in the South...
Our planet just set a scary new carbon dioxide record

Our planet just set a scary new carbon dioxide record

SOURCE: Grist DATE: March 6, 2019 SNIP: Our planet’s level of carbon dioxide in the atmosphere reached a new, jarring record last month. Scientists from Scripps Institution of Oceanography announced on Tuesday that February’s average carbon dioxide measurement was 411.66 parts per million as measured in Mauna Loa, Hawaii. Since humanity’s greenhouse gas emissions were at an all-time high last year, a new record was expected. What was shocking was that it occurred so early in the year: Earth’s carbon dioxide levels typically peak in May, when the vast northern forests of North America and Asia are just beginning to green up. Setting a new record in February is “rare,” according to Scripps. “In most years, the previous maximum is surpassed in March or April. The February record breaking is a measure of just how fast CO2 has been rising in the past months,” said Scripps CO2 Group Director Ralph Keeling. This year’s carbon dioxide level is expected to peak around 415 parts per million in...
Mauna Loa carbon dioxide forecast for 2019

Mauna Loa carbon dioxide forecast for 2019

SOURCE: UK Met Office DATE: January 26, 2019 SNIP: The mean atmospheric carbon dioxide concentration will continue to rise in 2019 due to emissions from fossil fuel burning, land use change and cement production, with this year’s annual rise potentially being larger than those of the previous two years due to a temporary weakening of the land carbon sink caused by climate...