Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Politics : Politics of Energy -- Ignore unavailable to you. Want to Upgrade?

To: teevee who wrote (11185)	7/13/2009 4:19:27 PM
From: RetiredNow	Read Replies (1) \| Respond to of 86355

Good post in Wikipedia on CO2 toxicity. It talks about how runaway increases in CO2 in our atmosphere can be fatal to most animal life forms. Check it out: en.wikipedia.org Toxicity See also: Carbon dioxide poisoning Main symptoms of Carbon dioxide toxicity, by increasing volume percent in air.[2][36]. Carbon dioxide content in fresh air (averaged between sea-level and 10 hPa level, i.e. about 30 km altitude) varies between 0.036% (360 ppm) and 0.039% (390 ppm), depending on the location (see graphical map of CO2). Prolonged exposure to moderate concentrations can cause acidosis and adverse effects on calcium phosphorus metabolism resulting in increased calcium deposits in soft tissue. Carbon dioxide is toxic to the heart and causes diminished contractile force.[36] Toxicity and its effects increase with the concentration of CO2, here given in volume percent of CO2 in the air: * 1%, as can occur in a crowded auditorium with poor ventilation, can cause drowsiness with prolonged exposure.[2] * At 2% it is mildly narcotic and causes increased blood pressure and pulse rate, and causes reduced hearing.[36] * At about 5% it causes stimulation of the respiratory centre, dizziness, confusion and difficulty in breathing accompanied by headache and shortness of breath.[36] * At about 8% it causes headache, sweating, dim vision, tremor and loss of consciousness after exposure for between five and ten minutes.[36] A natural disaster linked to CO2 intoxication occurred during the limnic eruptions in the CO2-rich lakes of Monoun and Nyos in the Okun range of North-West Cameroon: the gas was brutally expelled from the mountain lakes and leaked into the surrounding valleys, killing most animal forms. During the Lake Nyos tragedy of 1988, 1700 villagers and 3500 livestock died. Due to the health risks associated with carbon dioxide exposure, the U.S. Occupational Safety and Health Administration says that average exposure for healthy adults during an eight-hour work day should not exceed 5,000 ppm (0.5%). The maximum safe level for infants, children, the elderly and individuals with cardio-pulmonary health issues is significantly less. For short-term (under ten minutes) exposure, the U.S. National Institute for Occupational Safety and Health (NIOSH) and American Conference of Government Industrial Hygienists (ACGIH) limit is 30,000 ppm (3%). NIOSH also states that carbon dioxide concentrations exceeding 4% are immediately dangerous to life and health.[37] Adaptation to increased levels of CO2 occurs in humans. Continuous inhalation of CO2 can be tolerated at three percent inspired concentrations for at least one month and four percent inspired concentrations for over a week. It was suggested that 2.0 percent inspired concentrations could be used for closed air spaces (e.g. a submarine) since the adaptation is physiological and reversible. Decrement in performance or in normal physical activity does not happen at this level.[38][39] These figures are valid for pure carbon dioxide. In indoor spaces occupied by people the carbon dioxide concentration will reach higher levels than in pure outdoor air. Concentrations higher than 1,000 ppm will cause discomfort in more than 20% of occupants, and the discomfort will increase with increasing CO2 concentration. The discomfort will be caused by various gases coming from human respiration and perspiration, and not by CO2 itself. At 2,000 ppm the majority of occupants will feel a significant degree of discomfort, and many will develop nausea and headaches. The CO2 concentration between 300 and 2,500 ppm is used as an indicator of indoor air quality. Acute carbon dioxide toxicity is sometimes known by the names given to it by miners: blackdamp (also called choke damp or stythe). Miners would try to alert themselves to dangerous levels of carbon dioxide in a mine shaft by bringing a caged canary with them as they worked. The canary would inevitably die before CO2 reached levels toxic to people. Carbon dioxide ppm levels (CDPL) are a surrogate for measuring indoor pollutants that may cause occupants to grow drowsy, get headaches, or function at lower activity levels. To eliminate most indoor air quality complaints, total indoor CDPL must be reduced to below 600. NIOSH considers that indoor air concentrations that exceed 1,000 are a marker suggesting inadequate ventilation. ASHRAE recommends they not exceed 1,000 inside a space.

To: teevee who wrote (11185)	7/13/2009 4:34:09 PM
From: RetiredNow	Read Replies (1) \| Respond to of 86355

Another reply to your post to add to my Wikipedia response. Check out the CO2 levels on a geological timescale. You'll notice that we're actually in a CO2 impoverished era. That's good news, right? Doesn't that mean that humans can survive much higher levels of CO2, because the Earth has had higher CO2 levels in the past? Wrong. Humans have not been around that long. Would humans have survived in previous geological periods of high CO2 levels? Not in our present evolutionary form. Abrupt CO2 level increases in regions of high volcanic activity has resulted in the death of animal life forms. If our atmosphere experiences runaway CO2 increases, then we will die. We should all be concerned about whether we are setting in motion runaway processes that can result in our own extinction. If you aren't concerned with that, then at the very least, you should be concerned with the financial impact of a rapidly changing climate due to CO2 increases in our atmosphere.