Climate change on Jupiter

A popular argument against anthropogenic global warming is that other planets in the solar system are warming (Fred Thompson even seems to be making it one of his campaign policies). Last week, I received an intriguing email from John Cross speculating that perhaps Jupiter's climate change were the effects of the Shoemaker-Levy 9 comet collision. None of the papers on the topic seemed to indicate any long term effects from the comet impact but scratching around the peer reviewed literature did dig up some interesting facts about Jupiter's climate.

Between 1998 and 2000, three White Ovals (giant vortices) on Jupiter merged and formed a new oval, approximately the size of Earth. Initially, it was white but turned brown and then red in 2005. The official name of the red spot is "Oval BA" although it's more popular nickname "Red Spot Jr" has considerably more cachet.

Steps in the consolidation of three "white oval" storms into one over a three-year span of time.

What fuels Jupiter's storms?

On Jupiter, the sun's energy is only 4% of the level we receive on earth, nowhere near enough to fuel its turbulent, planet-sized storms. Jupiter radiates into space almost twice the heat it absorbs from the sun. This internal heat source, via moist convection, converts heat flow into the kinetic energy that fuels Jovian storms (Ingersoll 2000, Gierasch 2000).

How is Jupiter's climate changing?

Temperature is relatively uniform on Jupiter - the temperature at the poles is nearly the same as at the equator. This is due to the chaotic mixing of heat and airflow from vortices (eg - the White Ovals). The oscillatory motions of the White Ovals ceased after they merged, dampening the movement of heat from Jupiter's equator to its south pole. The latitudes near 34°S, the same latitude where Red Spot Junior is located, are predicted to become barriers preventing the mixing of heat and airflow. If so, Jupiter's equatorial regions will become warmer and its poles will become cooler. Average temperature at some latitudes could change by as much as 5.5° Celsius (Marcus 2006).

Implications for Earth's climate

While Jupiter's storms are fueled from an internal heat source, Earth's climate gets its energy from the sun (which hasn't shown any long term warming trend for over 50 years). Additionally, Jupiter's climate change is due to shifts in internal turbulence rather than an external forcing. So what is the connection between Jupiter's climate change and Earth's global warming? There is none.