How to compute the change in static temperature using only altitude? I'm given an initial altitude of FL290 in ISA conditions, and the aircaft is said to climb to reach FL310. How can I use this to calculate the change in static temperature between the two flight levels?

I know that the formal term is the lapse rate and generally lapse rate decreases around 2 degrees Celsius per 1000 feet of climb.

Would I use a ISA temperature table to figure out the temperature for the initial altitude and then use the lapse rate to calculate the change in temperature when it climbs to reach FL310?
I found the answer, it's literally looking at ISA temperature table of the initial FL. The lapse rate is 2degrees per 1000 feet of climb. You would see what the initial temperature is for your FL and then you minus the lapse rate for the climb that you are given. So in this case, the lapse rate would be 4degrees as it climbs 2000 feet.