1. Increased Oxygen Levels: The oxygen levels during the Jurassic Period were much higher than today's levels. Estimates suggest that oxygen concentrations could have been as high as 25-35% compared to the current 21%. This abundance of oxygen supported a thriving and diverse ecosystem.
2. Dominance of Carbon Dioxide: Carbon dioxide (CO2) concentrations were also higher during the Jurassic Period, estimated to have been around 1000-2000ppm (parts per million). These higher CO2 levels contributed to a "greenhouse effect," maintaining a warmer and more humid climate globally.
3. Lower Atmospheric Pressure: The overall atmospheric pressure during the Jurassic Period was lower compared to today's levels. Lower pressure favored higher rates of evaporation and likely contributed to the moisture in the atmosphere.
4. Low Ozone Levels: Ozone (O3) levels in the atmosphere were significantly lower during the Jurassic Period. This absence of ozone protection meant that ultraviolet (UV) radiation from the sun reached the Earth's surface more intensely. Plants and animals had to adapt to these high UV levels.
5. Higher Greenhouse Gas Concentrations: In addition to CO2, other greenhouse gases such as methane (CH4) and nitrous oxide (N2O) were also present in elevated concentrations. These gases further enhanced the "greenhouse effect" and contributed to the warmer global temperatures.
6. Volcanic Activity and Aerosols: Volcanic activity was frequent during the Jurassic Period, releasing large amounts of aerosols and ash into the atmosphere. These aerosols would have had a cooling effect, counterbalancing some of the warming caused by higher greenhouse gases.
It's important to note that the Jurassic Period was not a monotonous time, and the atmospheric conditions likely fluctuated over its approximately 50 million-year span. However, the overall characteristics mentioned above provide a general picture of the atmospheric composition and conditions during this geological era.
