Climate The climate of the Jurassic was generally warmer than that of present, by around , with atmospheric carbon dioxide likely about four times higher. Intermittent "cold snap" intervals are known to have occurred during this time period, however, interrupting the otherwise warm greenhouse climate. Forests likely grew near the poles, where they experienced warm summers and cold, sometimes snowy winters; there were unlikely to have been ice sheets given the high summer temperatures that prevented the accumulation of snow, though there may have been mountain glaciers. Dropstones and glendonites in northeastern Siberia during the Early to Middle Jurassic indicate cold winters. Alt URL The ocean depths were likely warmer than present, and coral reefs grew 10° of latitude further north and south. The Intertropical Convergence Zone likely existed over the oceans, resulting in large areas of desert and scrubland in the lower latitudes between 40° N and S of the equator. Tropical rainforest and tundra biomes are likely to have been rare or absent. The Jurassic also witnessed the decline of the Pangaean megamonsoon that had characterised the preceding Permian and Triassic periods. Variation in the frequency of wildfire activity in the Jurassic was governed by the 405 kyr eccentricity cycle. Thanks to the breakup of Pangaea, the hydrological cycle during the Jurassic was significantly enhanced.
Climate The climate of the Jurassic was generally warmer than that of present by around  with atmospheric carbon dioxide likely about four times higher Intermittent "cold snap" intervals are known to have occurred during this time period however interrupting the otherwise warm greenhouse climate Forests likely grew near the poles where they experienced warm summers and cold sometimes snowy winters; there were unlikely to have been ice sheets given the high summer temperatures that prevented the accumulation of snow though there may have been mountain glaciers Dropstones and glendonites in northeastern Siberia during the Early to Middle Jurassic indicate cold winters Alt URL The ocean depths were likely warmer than present and coral reefs grew 10° of latitude further north and south The Intertropical Convergence Zone likely existed over the oceans resulting in large areas of desert and scrubland in the lower latitudes between 40° N and S of the equator Tropical rainforest and tundra biomes are likely to have been rare or absent The Jurassic also witnessed the decline of the Pangaean megamonsoon that had characterised the preceding Permian and Triassic periods Variation in the frequency of wildfire activity in the Jurassic was governed by the 405 kyr eccentricity cycle Thanks to the breakup of Pangaea the hydrological cycle during the Jurassic was significantly enhanced