800,000 year high for Greenhouse Gases

Headlines with scary numbers always appeal to me. It begs the question of how do they know this and how accurate this figure is but I am sure the article will tell me. More importantly, what does it mean? A first guess is that the answer is unlikely to be a happy one for mankind.

Greenhouse Gases Highest For 800,000 Years-Study [PlanetArk]

OSLO - Greenhouse gases are at higher levels in the atmosphere than at any time in at least 800,000 years, according to a study of Antarctic ice on Wednesday that extends evidence that mankind is disrupting the climate.

Edit: After reading the article I am not really any the wiser on any of my earlier questions.

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