1) If insolation falls, global temps can be lower even with more greenhouse gases in the atmosphere. If insolation stays constant, increasing greenhouse gases w

1) If insolation falls, global temps can be lower even with more greenhouse gases in the atmosphere. If insolation stays constant, increasing greenhouse gases will increase the amount of energy trapped under the atmosphere (aka heat). Insolation varies slowly based on orbital variations, which created the historical record you’re referencing. Right now we don’t have any evidence that insolation is declining fast enough to offset the effect of the greenhouse gases we are adding to our atmosphere. Which makes sense because we independently measure an upward trend in heat trapped in the atmosphere. 2) In the global historical record the peak of CO2 has usually trailed the peak of temperature. Again this reflects changes in insolation: as more sunlight makes the climate get hotter, more CO2 is released. Then as sunlight declines, the climate cools but the CO2 lingers for a while. This is actually really concerning because it implies that we should expect a natural spike of CO2 on top of our anthropogenic spike of CO2, meaning it will get much worse than it even looks now. 3) Yes, “life” can thrive at higher temps, but our bodies, culture, and infrastructure are adapted for these temps. And it’s not just temperature; sea level rise (primarily driven by the metric expansion of water as it is heated) will inundate large amounts of livable land including some of the most productive and populated. Maybe good for neritic life, but bad for us. 4) The negative and positive effects don’t necessarily balance. Again, losing dry land to the sea is not balanced by increased ocean algal growth. “I destroyed your house, but gave you more fertilizer for your lawn”—does that seem like a fair trade?