Calvin 2 (William H., Professor of Biology – University of Washington, “A Brain for All Season”, http://WilliamCalvin.com/BrainForAllSeasons/ NAcoast.htm)
The population-crash scenario is surely the most appalling. Plummeting crop yields will cause some powerful countries to try to take over their neighbors or distant lands – if only because their armies, unpaid and lacking food, will go marauding, both at home and across the borders. The better-organized countries will attempt to use their armies, before they fall apart entirely,to take over countries with significant remaining resources, driving outor starving their inhabitants if not using modern weapons to accomplish the same end: eliminating competitors for the remaining food. This will be a worldwide problem – and could easily lead to a Third World War – but Europe's vulnerability is particularly easy to analyze.The last abrupt cooling, the Younger Dryas, drastically altered Europe's climate as far east as Ukraine. Present-day Europe has more than 650 million people. It has excellent soils, and largely grows its own food. It could no longer do so if it lost the extra warming from the North Atlantic.