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If we end up with a runaway greenhouse effect, it's possible that Earth could become Venus-like, with surface temperatures of hundreds of degrees. This would pr

• danielweber 12y ago
  it's possible that Earth could become Venus-like, with surface temperatures of hundreds of degrees How much CO2 would you need in the atmosphere to do that??
  • NickM 12y ago
    CO2 isn't the only greenhouse gas, or anywhere near the most powerful. There are immense reserves of methane gas frozen under the arctic. If that gas were suddenly released all at once due to the ice caps melting, it could be truly catastrophic. Bear in mind that hundreds of millions of years ago, Venus used to have an atmosphere much more like Earth's, and there may have even been liquid water on the surface. But a runaway greenhouse effect caused all that to change dramatically. It took a very long time, but obviously Venus didn't have people there to help speed things along.
    • lutusp 12y ago
      > CO2 isn't the only greenhouse gas, or anywhere near the most powerful. There are immense reserves of methane gas frozen under the arctic. If that gas were suddenly released all at once due to the ice caps melting, it could be truly catastrophic. Yes, true, with one mitigating factor -- methane doesn't stay in the atmosphere very long. It breaks down fairly rapidly. It's a much more efficient greenhouse gas than CO2, but it's short-lived.