The Earth Has A Fever
For the last 2.5 million years, global temperature has shifted between cold glacial periods that last for around 100 000 years, and warmer interglacial periods that last for around 10 000 years. Right now we are in an interglacial period. 20 000 years ago the Earth was cold. Around 15000 years ago it started to warm up, this was the end of the last glacial period. Over the last 10 000 years the climate has been warm with minor fluctuations, however over the last 1000 years the climate has been fairly constant with small fluctuations …show more content…
By analysing gases trapped when the ice formed and the chemistry of the ice they can tell what the temperature was each year and work out how it has changed over time, for example high CO2 levels in ice indicate a warm climate at that time. Pollen analysis is another way of checking temperature levels. Scientists know the climatic conditions that plants live in now, and when they find preserved pollen from similar plants, it helps them understand what the climate was like when that pollen was produced. Lastly, dendrochronology is another useful way to find past temperature levels as when a tree grows it forms a new tree ring each year, the tree rings are thicker in warm, wet conditions. Scientists take cores and count the rings to find the age of the tree. Tree rings can reliably show and date climate conditions up to 10 000 years ago. These pieces of evidence definitely prove Al Gore’s statement by showing that there is evidence in nature and historical records that global warming is increasing, mainly due to anthropological reasons.
This increase in global temperatures because of humans has many impacts globally. Gore points out the increase in wildfires, the melting glaciers and gradual drying up of all continents as undeniable proof of global warming. The number of Category 4 and 5 hurricanes has doubled in the last 30 years and global sea levels could rise 20 feet by