y well unimaginable.

    is most alarming is t ural ply rattle Earter. As Elizabet, ing in ternal force, or even any t emperature back and fortly, and as often, as to be to be, s and terrible feedback loop,”

    probably involving tions of tterns of ocean circulation, butall tood.

    One t ter to t tiness (and ty) of nortream to so trying to avoid a collision. Deprived of tream’s itudes returned to cions. But t begin toexplain veer as before. Instead, ranquility knoime in which we live now.

    to suppose t tretcic stability s much longer.

    In fact, some auties believe t   before. It isnatural to suppose t global  as a useful counterendency to plunge back into glacial conditions.  ed out, uating and unpredictable climate “t t todo is conduct a vast unsupervised experiment on it.” It ed, y t first seem evident, t an ice age migually be induced by arise in temperatures. t a sligion rates andincrease cloud cover, leading in titudes to more persistent accumulations of snow.

    In fact, global o pohern Europe.

    Climate is t of so many variables—rising and falling carbon dioxide levels, ts of continents, solar activity, tately c it is asdifficult to compres of t as it is to predict ture. Mucake Antarctica. For at least ty million years after it settled over tarctica remained covered in plants and free of ice. t simply s havebeen possible.

    No less intriguing are te dinosaurs. tisStepes t forests itude of togreat beasts, including tyrannosaurus rex