Correcting The Earth To Match The Meter
The kilometer was intended to be 1/40,000 of the polar circumference of the Earth. Due to small surveying error, the polar circumference is actually 40,007.863 km.
How much seawater would we need to remove to make the sea level circumference PRECISELY 40,000 km? 
7.863 km / 2π ; 1250 meters. During the last ice age, the sea dropped 120 meters as water became glaciers. So, we either make 10 ice ages worth of ice, or we launch the water to colonies in space.