re: True or False: climate change

quote:

---

Now to your chart. Where would you peg the start of the modern warming period? Your right the only concrete date for a cause is the volcanic eruptions. But based on your graph the warming starts at leased in the middle of the 19th century not the 20th. Based on your graph 1800 is reasonable. I'm biased to 1820 because it's the first date I learned for the end of the cold and start of the new. The paper I referenced picks 1850 and I don't think you could argue no warming until 1950 on your chart.

My argument to you is that climate change is normal and the global temperatures never are the same century to century. I can bring massive evidence that the current cycle is a natural cycle!

---

Giving a precise date is a mug's game, since emissions rose gradually over time. Nobody's gonna be able to pin down THE year human forcings overtook natural forcings, although I think you could make the case for 1960 as a late boundary since that was this century's local maximum for solar irradiance.

The salient point is that there aren't any natural forcings that can explain the sharp rise between then and now. I'm curious what "massive evidence" you would bring to bear on this. Nobody disputes that past temperature fluctuations have been caused by solar or volcanic forcings, this is discussed extensively in the IPCC. But we have proxy evidence pointing to natural forces. Now, even with direct observation, there's none.