"We've already passed a safe threshold for coral reef ecosystems in terms of climate change; we believe that a safe level for CO2 is below 350 parts per million," said Alex Rogers of the Zoological Society of London and International Programme on the State of the Ocean, who helped organise today's meeting.
That's the level outlined by policymakers as a safe threshold for climate change.
This may be of biological significance because high simultaneous exposure may exceed a safe threshold.
There is uncertainty as to whether there is a safe threshold for drinking alcohol during pregnancy.
Hence, a safe threshold for drinking in pregnancy has not been conclusively established [ 9- 11].
And apparently we're not doing much to stop it: according to Professor Kevin Anderson, one of Britain's leading climate scientists, we've already blown our chances of keeping global warming below the "safe" threshold of 1.5 degrees.
If frozen water packs are improperly conditioned and/or vaccine refrigerators are malfunctioning, the internal temperature of the vaccine carrier can fall below the safe threshold to carry these vaccines.
However, official estimates of fetal doses after the Chernobyl explosion, even in the most contaminated regions of Germany, were < 1 mSv (UNSCEAR 2000), far below the presumed safe threshold.
More recently, Fischer et al. [ 40] reported that already after 30 min of HCA at 15°C the oxygen saturation of the frontal cortex as measured on near infrared spectroscopy (NIRS) drops below the relatively safe threshold of 60%, increasing the risk of serious adverse outcomes (p = 0.038).
The tissue oxygen monitor appears to define a new, lower safe threshold for transfusion.
