4 ms·
why do they get to start the annual temperature anomaly graph at around -.3 in 1900.
by ouid 7y ago
why do they get to start the annual temperature anomaly graph at around -.3 in 1900.
- new_realist 7y agoBecause 0 is the average temperature from 1961-1990.
- lopmotr 7y agoIt's not a quantity that has any natural zero, nor is time (year since Jesus?). So you can start it wherever you want.
- xxgreg 7y agoPedantic answer... You could start at 0 Kelvin. https://en.wikipedia.org/wiki/Absolute_zero https://en.wikipedia.org/wiki/Absolute_zero
- ouid 7y agothat's not true at all. We're trying to measure the human impact on global temperature. The natural zero is whatever our best guess for the temperature would be without human intervention.
- lopmotr 7y agoIf it was constant, I'd agree, but the natural temperature was always changing and whatever it would have been today will also be changing. So you'd be graphing a different quantity, f(t) = temperature(t) - natural_temperature(t). From such a graph, you wouldn't be able to tell if a change was a change in the actual temperature or just a change in the predicted natural temperature. A predicted natural cooling would look the same as a human-caused warming.
- ouid 7y agoThis is already the case.