Once Britain connected to mainland Europe (and a bit of Ireland connected to Britain) about 6000 BC in a northern area called Doggerland. Then the sea-level rose.... it's a good thing the far left wasn't around to blame global warming on inventions like "blacksmithing tools, carpenter tools, and kitchen tools " ...how about also pottery, clothes, plumbing, roads, ...(looking at wikipedia)...middle ages windmills.