The end of the last California ice age 10,000 years ago did the final carving of Yosemite Valley. It’s part of the 400-mile-long stretch of granite we now call the Sierra that tectonic forces pushed upward over 2.4 million years ago. The global warming that followed the end of the last ice age gets credit for creating the Rodney Dangerfield of California’s great natural wonders — the Sacramento San Joaquin Delta. Before temperatures started heating up to force the retreat of the vast glaciers that once covered a large swath of what is today eastern California, the sea level was more than 300 feet lower with the edge of present-day San Francisco nearly 20 miles from the ocean. The Great Central Valley was a massive inland sea. And at the bottom of that sea was what is today the Delta.