One of the most important factors in understanding climate is the time it takes from an increase in CO2

to the corresponding , stabilized temperature increase


Before more precise calculations are made, it is important that intuition follows.


We can start from how CO2 content and temperature have varied over the last 500,000 years







Historical temperature and CO2 are plotted on a cloud of points (scatter-plot)

In the same way, all NASA measurements of temperature and CO2 are added

of recent measurements, last 100 years.


The above picture consists only of facts and one may wonder why all the recent measurements

stick out like a sore thumb.


The following thought-experiment clarifies:

If 100 years of emissions were made in a single day, the Earth would not have time at all

to warm up. One could conclude climate sensitivity =cs= 0 (red line)





The conclusion seems to be that the IPCC determined climate sensitivity from the unstabilised stick

which exhibits exactly cs=3

This is only the value telling of how fast the last 100 years of emissions have occurred and the value has nothing

to do with climate sensitivity.


This may explain why the IPCC miscalculates the forecast (+2C in 2100) , it miscalculates the

the remaining emissions budget (which is a mathematical consequence of cs)

and it miscalculates whether global temperatures will stop when emissions are stopped.


If 100 years of emissions were made over 50 years, you could

determine climate sensitivity=cs= 1.5 (blue line ).

We see that the faster emissions are made, the lower the climate sensitivity appears to be,






If 100 years of emissions were made over 200 years, we could

determine climate sensitivity=cs= 6 (green line )




If 100 years of emissions were made over 700 years, we could

guess climate sensitivity=cs= 36 , just by roughly estimating the angles.


This is just meant to give an intuitive feel.


If 100 years of emissions occur over a longer period than 700 years, then the stick

will settle into the cloud. It makes sense that the scientists who will come in 10,000 years,

won't find any stick sticking out, in the same way

just as today's scientists haven't found sticks in the scatterplot diagram,


Let's call this an intuitive guess:

Our planet exhibits a time constant of 500 to 700 years.


It is also consistent with the fact that the current rate of temperature increase is 0.035 and that this rate

requires 500-700 years to come into harmony with the cloud.


From there we can calculate that the climate sensitivity may be in the range cs=30-40

by solving the second degree  equation

t= -33.137407378 + 19.888205077 * cs -0.047279468 * cs^2


With cs=36 one can make workable projections, which the IPCC has shown cannot be done with cs=3






Extremely serious consequence:


If the above rules of thumb are correct, the Earth's temperature will continue to rise for 500 to 700 years

after all emissions have stopped.