[James001]

Thank god for negative feedback loops eh? I'm actually glad we have more CO2 in the atmosphere, because it will increase biodiversity and agricultural yields. I don't see any evidence that climate change is proceeding at a fast enough pace to cause damage.

[kristopolous]

There's a pretty solid factual case for quantifiable damage here: floods in Louisiana, Texas, India, West Virginia and France and fires in California, Portugal and Canada. There's also decreased crop yield due to droughts and decreased fish yield due to ocean acidification. This is non-zero.

[James001]

Almost all of those cases can have explanations that are not global warming related.

For example, in Canada those fires were huge because of too-efficient fire suppression methods. Not enough controlled fires were done in that area and Fort Mcmurray expanded beyond its Fire Protection zone.

Not every weather-related catastrophe is caused by global warming, that just harms the credibiltiy of that argument

[mikeash]

What's the evidence for increased CO2 leading to increased biodiversity and agricultural yields?

[HillRat]

Under conditions of increased CO2 availability, plants tend to decrease waster usage and sequester more carbon. Growth rates are faster, but require increased mineral availability. Unfortunately, nitrogen levels in plants decrease in high-atmospheric CO2 conditions, which leads to lower protein concentrations. As a result, consumption crops provide less energy and nutrition when consumed.

So, all in all, the downsides outweigh the upsides -- faster growth, lower nutrition, more aggressive soil depletion, and increased water runoff. On the bright side, carbon sequestration increases up to 40%, so the efficacy of planting forests as a sequestration measure will increase.

As for biodiversity -- well, dieoffs are already outpacing speciation. Unless you believe in abiogenesis, the trendline is moving sharply downward.

[monk_e_boy]

Wasn't CO2 much higher in the past, hence why plants were so massive and could support big dino's.