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Is this true? This is something I question a lot. Intuition tells me that the greenhouse effect of CO2 and other gasses determines derivative of climate change,

Is this true? This is something I question a lot. Intuition tells me that the greenhouse effect of CO2 and other gasses determines derivative of climate change, but its often presented like it sets the absolute average temperature. That is, if we stopped producing CO2 completely back to pre-industrial levels (somehow), would we expect the globe to get warmer? Or are both statements true because excess CO2 naturally leaves the atmosphere into space + gets absorbed into the ocean?

AnthonyMouse 8y ago
Part of the problem with climate change is that some of the effects are self-sustaining. For example, snow and ice reflect light back into space. If the temperature increases then more of the ice melts, so more light is absorbed by the earth which raises the temperature. Then even if you get rid of the carbon, the temperature stays higher because the ice is gone and is no longer reflecting light back into space. And the ice is from the last ice age, it doesn't just refreeze on its own -- especially now that the temperature is higher. Meanwhile with higher temperatures there are more areas of drought, which means less vegetation grows there, which means those areas can absorb less carbon. And that too is sticky. If the temperature stays higher then there continue to be droughts and less vegetation. What this means is that we need to stop emitting carbon ASAP, and then on top of that ultimately do something to reverse the effects and actively work to get the temperature back down to where it was, because it may not be able to fix itself. We think of the Earth as a self-regulating system, but that isn't because it's stable, it's because it's adaptive. Earth's temperatures have been higher than this and still sustained life, but none of that life was humans, and the previous changes were accompanied by mass extinctions.
- chupasaurus 8y ago
  > Then even if you get rid of the carbon, the temperature stays higher because the ice is gone and is no longer reflecting light back into space. And the ice is from the last ice age, it doesn't just refreeze on its own -- especially now that the temperature is higher. Check the historical data on CO₂ levels from antarctic ice. It correlates perfectly with the ice ages (we had samples of ~400K years covering 3 previous), and guess what, we are now on the brink of a next one.
  - AnthonyMouse 8y ago
    Were on the brink of a next one, on the geological timescale. Before we started burning all this carbon and went hard the other way.

AnthonyMouse 8y ago

Part of the problem with climate change is that some of the effects are self-sustaining. For example, snow and ice reflect light back into space. If the temperature increases then more of the ice melts, so more light is absorbed by the earth which raises the temperature. Then even if you get rid of the carbon, the temperature stays higher because the ice is gone and is no longer reflecting light back into space. And the ice is from the last ice age, it doesn't just refreeze on its own -- especially now that the temperature is higher. Meanwhile with higher temperatures there are more areas of drought, which means less vegetation grows there, which means those areas can absorb less carbon. And that too is sticky. If the temperature stays higher then there continue to be droughts and less vegetation. What this means is that we need to stop emitting carbon ASAP, and then on top of that ultimately do something to reverse the effects and actively work to get the temperature back down to where it was, because it may not be able to fix itself. We think of the Earth as a self-regulating system, but that isn't because it's stable, it's because it's adaptive. Earth's temperatures have been higher than this and still sustained life, but none of that life was humans, and the previous changes were accompanied by mass extinctions.

chupasaurus 8y ago
> Then even if you get rid of the carbon, the temperature stays higher because the ice is gone and is no longer reflecting light back into space. And the ice is from the last ice age, it doesn't just refreeze on its own -- especially now that the temperature is higher. Check the historical data on CO₂ levels from antarctic ice. It correlates perfectly with the ice ages (we had samples of ~400K years covering 3 previous), and guess what, we are now on the brink of a next one.
- AnthonyMouse 8y ago
  Were on the brink of a next one, on the geological timescale. Before we started burning all this carbon and went hard the other way.