it isn't & if those temps had gone down 1.5 instead after the little ice age period the human population would now not be 8.2bn. the human population in 1700 was 600m (lost 200m during the black death - however people died earlier then anyway & people just had more babies). warmer temps mean higher farming yields, you literally put plants in greenhouse to increase the rate of growth & to get higher yields. trees live on co2 as do all plants. make all areas plantable, they can feed the world.
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