The New York Magazine posted, “The Uninhabitable Earth” by David Wallace-Wells. Some observers think that this posting is so bizarre that it must be a parody; meant to be something like a posting on the ONION.
I have been planning to discuss some information about CO2. When I read Part V of Mr. Wallace-Wells essay subtitled “Unbreathable Air”, I had to make it part of the discussion to illustrate why some consider the New York Magazine’s posting is a parody. Wallace-Wells notes:
“Our lungs need oxygen, but that is only a fraction of what we breathe. The fraction of carbon dioxide is growing: It just crossed 400 parts per million, and high-end estimates extrapolating from current trends suggest it will hit 1,000 ppm by 2100. At that concentration, compared to the air we breathe now, human cognitive ability declines by 21 percent.
Where is he getting his information? Let’s look at what experts have to say about CO2 .
CO2 is an asphyxiant gas and not classified as toxic or harmful. The American Conference of Governmental Industrial Hygienist say that the TLV is 5,000 ppm. The Threshold Limit Value (TLV) is the level which a worker can be exposed to day after day for a lifetime without adverse effects. Concentrations up to 1% (10,000 ppm), will make some people feel drowsy according to some sources. Levels of 70,000 to 100,000 may cause suffocation. So, Wallace-Wells’ value of 1000ppm is truly a laughable statement. Perhaps anyone who reads the “Uninhabitable Earth” will experience a cognitive decline of 21%.
Amplifying on the safe levels of CO2, a posting on WUWT titled “Life on Earth was nearly doomed by too little CO2” says
There’s little danger to humans of too much CO2 in the air they breathe. Even the Environmental Protection Agency says 1000 ppm is the safe limit for lifetime human exposure. Space shuttle CO2 alarms are set at 5,000 ppm, and the alarm in nuclear submarines is set at 8,000 ppm!
The WUWT posting has some interesting thoughts regarding low levels.
What few realize, however, is that during the last Ice Age too little CO2 in the air almost eradicated mankind. That’s when much-colder water in oceans (that were 400 feet shallower than today) sucked most of the carbon dioxide from the air; half of North America, Europe and Asia were buried under mile-high glaciers that obliterated everything in their paths; and bitterly cold temperatures further retarded plant growth.
In fact, Earth’s atmosphere had only about 180 parts per million CO2, compared to today’s 400 ppm: 0.018% then versus 0.040% today.
The Ice Age’s combined horrors – intense cold, permanent drought and CO2 starvation – killed most of the plants on Earth. Only a few trees survived, in the mildest climates. Much of the planet’s grass turned to tundra, which is much less nourishing to the herbivores prehistoric humans depended on for food and fur. Recent Cambridge University studies conclude that only about 100,000 humans were left alive worldwide when the current interglacial warming mercifully began.
The few surviving prey animals had to keep migrating to get enough food. That forced our ancestors to migrate with them, in temperatures that routinely fell to 40 degrees below zero (both Fahrenheit and Celsius). The Neanderthals had been living in relatively warm caves protected from predators by fires at the cave mouths. They had hunted their prey by sneaking through the trees – which no longer existed. They apparently couldn’t adapt, and starved. Cambridge found no evidence of genocidal warfare.
The most successful human survivors – who provided most of the DNA for modern Europeans – were nomads from the Black Sea region. The Gravettians had never had trees, so they invented mammoth-skin tents, held up by salvaged mammoth ribs. They also developed spear-throwers, to kill the huge beasts from a safe distance.
Equally important, Gravettians domesticated and bred wolves, to protect their tents from marauders, locate game animals on the broad tundra, and harry the prey into defensive clusters for easier killing. The scarcity of food in that Glacial Maximum intensified the dogs’ appreciation for the bones and bone marrow at the human camps.
When that Ice Age ended, moreover, CO2 changes didn’t lead the warming. The atmospheric CO2 only began to recover about 800 years
after the warming started.
cbdakota
Climate Change Sanity 