About 55million years ago, Earth's temperature suddenly shot up owing to a massive release of carbon dioxide into the atmosphere, new research have revealed. Scientists are warning that we should take note and cut carbon emissions to avoid a repeat.
Historically, Earth was much warmer. About 55 million years ago, temperatures were, on average, 8 degrees Celsius higher than they are now. There were crocodiles living off Greenland, and palm forests in Wyoming.
Suddenly, the levels of carbon-dioxide doubled and global temperatures increased by 5 degrees.
Previously, scientists had thought this warming had taken tens of thousands of years.
But now researchers Morgan Schaller and James Wright have been studying offshore clays dating from this period from Maryland and Delaware. They discovered a repeating pattern in the clay, resembling tree-rings, corresponding to a yearly cycle of rivers dropping more and less sediment into the ocean.
By looking at different isotopes of carbon present in each of the clay layers, including carbon-12, which is more easily taken up by living things, and carbon-13, which is more common in inorganic carbon sources, they found evidence for a huge injection of about 3000 billion tonnes of carbon into the atmosphere over a period of a few months.
Over the next 13 years, this dissolved into the shallower parts of the sea causing it to become acidic, killing off more deep sea species than at the end of the cretaceous which killed off the dinosaurs. It then took 150 000 years for things to return to normal.
This, they say, should help us to understand not only an interesting piece of Earth's early history, but also serves as the best model we have of the experiment we are doing to our climate by adding CO2 to the atmosphere by burning fossil fuels.
For a long time we've known a correlation between CO2 and glacial/interglacial periods. However, the timing seems to indicate an increase of temperatures preceding the increase in CO2 levels, with the interpretation that the rising temperatures drive the CO2 out of the oceans.
The inherent properties of water lead to a bounded chaotic oscillation of atmospheric temperature if driven by a constant solar input. If we start with a dry atmosphere over a wet planet, evaporation increases the greenhouse effect (since water is the major greenhouse gas), thus raising the air temperature, encouraging more evaporation, and increasing the capacity of the atmosphere to hold water. This positive feedback produces a rapid rise in temperature up to the point that the planet is covered with cloud which cuts off the surface heating but also reduces radiative loss, so it slowly cools down again. Hence the sawtooth temperature/time profile we find in ice cores.
As with many systems, proportional variation over a long enough time is not so much the problem. The rate of change is.
There's a significant difference between an asymptotic equilibrium and an inherently unstable and chaotic oscillator. CO2 is irrelevant. alancalverd, Wed, 16th Oct 2013
1. Do you accept that humans have released a significant volume of CO2 into the atmosphere?
The infrared absorption spectrum of carbon dioxide is negligible compared with that of water vapor, and the albedo of clouds is the principal determinant of heat input and output. Unfortunately all we know about these drivers of climate is that they are overwhelmingly large and very variable, as the IPCC admitted in its very first report.
Please provide peer reviewed citations to substantiate this. It would also be nice, for background understanding of your position, if you would answer the first of my three questions. Ophiolite, Thu, 17th Oct 2013
As far as water vs CO2 vs Methane & etc.
I note that the y-axes of the component graphs are not scaled, and the range of upgoing transmission is 2:1. Since the CO2 concentration doesn't vary much, that must all be due to water.
If that were the case, there would surely be less CO2 in the "warmer" ice?
I would bet the PETM (55 million years ago) had something to do with a nearby supernova or something astronomical. Notice how quickly the temperature returned to previous levels after the spike. Saw a talk by an IPCC scientist and even he admitted that the CO2 data didn't work very well for the PETM (Palaeocene-Eocene Thermal Maximum). Steve Wickson, Mon, 28th Oct 2013
I would say that climate change has definitely affected earth. A lot of typhoons and hurricanes that we are experiencing these days are due to low pressure and warmer water. Global warming is the cause of most of these natural disaster. To learn more about climatic changes go to http://www.researchomatic.com/essay/nature/ . You will see how little changes in the atmosphere can have ahuge impact on its inhabitatnts!
Not that Wikipedia is particularly trustworthy, but I see no reason for it to lie: