OK

Assume all you want, but I still think that any evidence that points to (or against) the existence of a "leak" in the Earth's atmosphere should be studied thoroughly. In other words, my opinion is that we should "understand" all the variables that are involved in the Earth's atmosphere. We should understand thoroughly why the Earth and other planets have the density of atmosphere that they do have. What are the natural forces and conditions that create an atmosphere around a planet and keep it there.

As you pointed out, the conditions on Mars are such that the temperature variation between night and day are extreme, this is similar to the extreme temperature variation on the moon. My understanding is that this "extreme" temperature variation is the result of the very "thin" atmosphere.
My assumption then is that IF the Earth's atmosphere decreases in density it should be possible to monitor that change by comparing the past temperature difference between night and day to the present temperature difference between night and day. For instance if the average temperature difference between night and day (in some specific area) was 5 degrees C in the past and now is 15 degrees. C, then that is an indication that something has changed, in my opinion the change would be in the (global) atmospheric density. Also if the temperature of the surface is higher now than it was in the past, then the reason may be that there is less atmospheric density to block the heat radiation from the sun.

I hope that you are not AFRAID to ask, study, or answer questions truthfully.

Weather archives can be found here.
http://www.ncdc.noaa.gov/cgi-bin/res40.pl?page=climvisghcnv2.html

Johannes