[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

[kristopolous]

better go change wikipedia then because it basically says 'climate change'.

[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.

[James001]

Really?

You're going to extrapolate from lower nitrogen levels in plants in higher CO2 conditions (without a citation, might i add) to higher CO2 levels causing overall lower nutrition? and more aggressive soil depletion? Keep in mind that obviously more plant growth means more plant decay which cycles back int othe ecosystem.

Are you trying to suggest that we should be decreasing agricultural yields so as to prevent soil depletion? There are better ways.

[mikeash]

"without a citation, might i add"

Odd card to play when your comment had no citations either, and you seem to be ignoring my request for them....

[James001]

It's well established that increased CO2 leads to increased plant biomass, thereby satisfying my claim that it leads to increased agricultural yield (as per greenhouses for example).

My claim that increased CO2 leads to more biodiversity is more tenuous but is more likely than a decrease in biodiversity, all other factors being controlled for.

[mikeash]

Typical double standard, your speculation is perfectly reasonable but the other guy's claims need scientific backing. Annoying, and not very convincing!

[monk_e_boy]

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

[mikeash]

Yes, CO2 was into the single-digit parts per thousand for much of the dinosaur era. I have no idea how that affected plant growth, but even if that's the cause, it seems tenuous to look at Mesozoic plant growth and assume modern agricultural crops will imitate them. Certainly far more tenuous than the evidence that climate change is causing damage and will cause more.

[monk_e_boy]

So you think that rising temperatures may be good for agriculture?

From a website:

As climate change leads to more frequent and intense natural hazards, it is expected that climate displacement will only increase in Bangladesh. The best estimates suggest that up to 18 million people may be displaced by sea level rise alone. http://displacementsolutions.org/ds-initiatives/climate-chan...

Europe us really struggling to deal with the migrants and refugees from Syria. I do wonder how we'll cope with future migrations. It really brings into perspective the idea of a border. Of a country. Just a man drew a line on a map.

[mikeash]

What gives you the impression I think that?

[James001]

It is not tenuous to suggest that modern agricultural crops will yield more in a higher CO2 environment (look into greenhouses). It is actually far less tenuous than speculating that CO2 is causing runaway global warming.