Climate change: How real? How soon? How political? Three experts with divergent perspectives state their top reasons for what they believe: Science supports global warming 1. Global warming is real. Multiple types of measurements and analyzes (weather stations, sea level monitors, borehole temperatures) agree with each other and show that the planet has warmed by 1.1 °C or 2 °F since about 1750. The magnitude of warming, and the rate of warming is beyond natural variation. 2. Warming varies with geography and with time. Climactic changes on planet Earth are not constant in time or space. High latitude regions may warm three times as much as the global average. Some regions may cool for extended periods. Short-term (annual, decadal, multi-decadal) Climactic changes are caused by sun spot cycles, El Nino/ La Nina, volcanic eruptions, and ocean current variations. These natural variations in time and space have existed in the past and should be expected in the future. 3. The global temperature record is best understood as the combination of a slow, long-term warming (un-natural/anthropogenic) and shorter-term fluctuations (natural). The combination is a record that has considerable variability: decade or more periods of temperature stagnation or decrease (1900-1910; […]