They would notice pretty quickly. The California GDP is ~2.6 trillion. NY is another 1.4. Together, they're about 20% of the US economy. And that's before we s

They would notice pretty quickly. The California GDP is ~2.6 trillion. NY is another 1.4. Together, they're about 20% of the US economy. And that's before we start thinking about agriculture. Of course, in that scenario, water becomes interesting.