The summary for Geoscience Currents #41 says:
"The percentage of all federal funding for research and development applied to the geosciences decreased from nearly 11% in 1996 to 6% in 2007, where it has held steady ever since. The total amount of federal research funding for geoscience research steadily increased between 1970 and 2004, peaking at $3.74 billion dollars. Since 2004, funding has steadily decreased, and in 2009 total federal research funding for geoscience research was $3.35 billion dollars. Total funding for geoscience research at universities peaked in 2004 at $1.1 billion dollars and decreased to $966 million dollars in 2007."
The full report breaks down geosciences among, ocean, atmosphere, earth, climate, and environmental sciences, and show absolute funding amounts as well as the relative shares.