If we wanted the Tropical Calendar to be a "Global Warming Calendar" we might adjust the number of days in each month to better fit the orbital motion of the Earth. We could make the length of each month correspond to a change of 30° relative to the Vernal Equinox. We would want the year to start in mid winter so the year would have to begin at the Winter Solstice or perhaps the next day.
Each of the months above fit this pattern with a Solstice or Equinox separating a block of three months. We could add the leap day at the end of the year where it was at one time or perhaps add it just before the Vernal Equinox to mark its significance as the date which we use to synchronize the calendar with the tropical year.
As the date of perihelion moves about in the year during the apsidal precession cycle periodic "calendar reforms" would be necessary to correct the lengths of the months to maintain the pattern of 30° monthly steps. It might be practical to do this every 1/12th of the 20,934 tropical year apsidal cycle which is about 1744 tropical years*. Leaving the calendar design somewhat open ended would allow changes to be made as our understanding of these changes increases and keep the calendar from becoming something rigidly preordained.
Supplemental: Basing the lengths of the months on the Earth's orbital motion was intended to focus attention of the Earth's heat balance and changes over time. There is a seasonal lag so temperatures do not exactly match the "seasons" but the highs and lows are delayed somewhat.
*Supplemental: Perihelion moves about 8.8° in 512 tropical years and 2.2° in 128 years. 512 years might be a little long to keep the system accurate and there is the problem of keeping people's interest in updating the calendar over that long a span of time. 128 years is more convenient because it could be done when the leap year is skipped but rearranging the calendar that often is a problem for historians.