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In a recent paper , Guy McPherson, Beril Sirmacek and Ricardo Vinuesa discuss Environmental thresholds for mass-extinction events. Authors point at an image by  Song et al. (2021) that shows how major mass extinctions over the past 541 million years (the Phanerozoic) are linked to temperature rises higher than 5.2°C and rates of change higher than 10°C/Myr. Earlier, a 2018 study by Strona & Bradshaw found that at 5°C rise, most life on Earth will be extinct (see box below on the right, from an earlier post) .   In the video below, authors Guy McPherson, Beril Sirmacek and Ricardo Vinuesa discuss their analysis 'Environmental thresholds for mass extinction events'. Authors point out that, next to temperature rise and rates of change, there are further variables such as rates of deforestation, ocean acidification and spreading of toxic substances that can additionally contribute to cause species to disappear. Accordingly,  many ...

By Andrew Glikson Earth and climate scientist Australian National University As the concentration of atmospheric CO₂ has risen to 408 ppm and the total greenhouse gas level, including methane and nitrous oxide, combine to near 500 parts per million CO₂-equivalent , the stability threshold of the Greenland and Antarctic ice sheets, currently melting at an accelerated rate , has been exceeded. The consequent expansion of tropics and the shift of climate zones toward the shrinking poles lead to increasingly warm and dry conditions under which fire storms, currently engulfing large parts of South America (Fig. 1), California, Alaska, Siberia, Sweden, Spain, Portugal, Greece, Angola, Australia and elsewhere have become a dominant factor in the destruction of terrestrial habitats. Figure 1. Sensors on NASA satellites Terra and Aqua captured a record of thousands of points of fire in Brazil in late August. Credit: NASA Earth Observatory Since the 18th century, combustion of fossil fuels ha...