Well, once again, our resident expert on all things that are right for us, Mr. liberal-progressive-socialist Tim Manello (who's made all his money in our capitalistic republic), is ranting. This time, about the horrors of CO2, with a staggering measurement of 400ppm on Mauna Loa. Let's see: dry air contains about .039% CO2 as a norm, which is 390ppm. Wow, Tim.
According to the CDC:
The chosen IDLH is based on the statements by ACGIH  that a 30-minute exposure at 50,000 ppm produces signs of intoxication, and a few minutes of exposure at 70,000 ppm and 100,000 ppm produces unconsciousness [Flury and Zernik 1931]. AIHA  reported that 100,000 ppm is the atmospheric concentration immediately dangerous to life. In addition, Hunter  noted that exposure to 100,000 ppm for only a few minutes can cause loss of consciousness.
400ppm? Now, while the world is dissolving around us, you state that the last time this horrific event occurred was 3-5 million years ago, before humans. And the highest concentrations were 350-600 million years ago, when plant like flourished.
Average global temperatures in the Early Carboniferous Period were hot- approximately 20 C (68 F). However, cooling during the Middle Carboniferous reduced average global temperatures to about 12 C (54 F). As shown on the chart below, this is comparable to the average global temperature on Earth today!
Similarly, atmospheric concentrations of carbon dioxide (CO2) in the Early Carboniferous Period were approximately 1500 ppm (parts per million), but by the Middle Carboniferous had declined to about 350 ppm -- comparable to average CO2 concentrations today!
Earth's atmosphere today contains about 380 ppm CO2 (0.038%). Compared to former geologic times, our present atmosphere, like the Late Carboniferous atmosphere, is CO2- impoverished! In the last 600 million years of Earth's history only the Carboniferous Period and our present age, the Quaternary Period, have witnessed CO2 levels less than 400 ppm.
By the way, what are you and Algore doing about this supposed problem? Driving all over? Flying all over? Running your mouths incessantly, which is also a source of CO2? Unless all the global warming alarmists are plant-based organisms and absorbing and metabolizing CO2, they're just adding to the problem. There are more people than ever before exhaling CO2 and cutting down more rain forest, which absorbs it. So, to solve the problem, we need to eliminate people and let the trees live, which will still leave lots of room for CO2 levels to rise again, with natural planetary cycles.