If Earth's magnetic field cools the planet to such a great extend as between summer and winter, then in the "When It Is Hot Enough!" post dated 16 Jan 2017; Earth is progressively cooler as the magnetic field builds up. The field strength is cooling and is working against the positive field gradient that dissipates heat into the surrounding, warming especially the polar regions.
\(????=\cfrac{1281.5}{2}=640.75\)
where it is assumed that mass extinction begins at the halfway point to the maximum heat dissipated at \(+max\) from now.
Earth is cool when its magnetic field is strong and is warm when its magnetic field is weak. When we factor in the cooling effect of the strength of the field then it is possible that Earth is hottest at the time we have previously marked as Mass Extinction. At this point the field gradient has gained sufficient value but the field strength remains low. The onset of mass extinction due to the heat is push forward to,
\(??=\cfrac{????}{2}=\cfrac{1281.5}{4}=320.37\) years from 4 Jul 2016
also assuming that mass extinction starts at the halfway point from now (4 Jul 2016) till earth experiences its maximum temperature.
Arbitrarily yours