Scientists studying what happened on Earth 55 million years ago when temperatures rose 6 degrees C (approx. 10 degrees F) over a short period of time say that many animals survived by getting much smaller. We humans may need to do the same thing – if we can. [readon]
And one of the challenges is that while the climate change event 55 million years ago happened over a period of 10,000 years, this time average temperature on Earth is now expected to rise by those same 6 degrees over less than 200 years.
According to a Climate News Network report by Paul Brown:
Animals, including humans, will shrink in size to survive in a warming world, according to scientists studying the last time the planet’s temperature rose rapidly by 6°C. What scientists call dwarfism was the successful strategy to avoid starvation for a large range of species including horses, many insects and even earthworms. The widespread response was partly to do with the heat but mostly because many plants became less nutritious, forcing mammals and insects to eat far more to survive.
In the next 100 years the combination of more carbon dioxide in the atmosphere and increased temperature could be “catastrophic” for an overpopulated world, according to one of the scientists involved.
With food supply drastically reduced, evolutionary forces suggest hobbit-sized humans who needed to eat less would have the greatest chance of survival.
These findings are the work of an international group of 30 scientists in the Bighorn Basin Coring Project, who are examining fossil deposits in rock strata in Wyoming to chart the period 55 million years ago when the Earth’s temperature rose suddenly – as it is expected to do this century.
There were mass extinctions, but the timescale gave some plants and animals time to adapt and move north and south to survive. Many species evolved quickly – dwarfism being one of the most widespread and successful strategies.
What worries the scientists is that this current warming period will take as little as 200 years, if the Intergovernmental Panel on Climate Changeis correct. This gives many long-lived species, for example trees, no time to evolve and migrate. Even mammals will struggle to move to new areas, because man has placed farmland and cities in the way.
In order to survive, all animals, including humans and insects, will be scrambling to eat a diminishing and less nutritious food supply.
Lower plant nutrition is caused by higher atmospheric carbon dioxide concentrations, rather than temperature itself. To get the same calories herbivores would have to eat more plant matter. Humans would be forced to grow more crops to get the same nutrition from food and spend more time eating it. Farm animals would also get smaller in response, making meat more difficult to obtain. Competition from insects eating food crops would be fierce.
Dwarfism is again expected to be a successful strategy for the survivors, enabling humans, animals and insects to mature earlier with less food and so reproduce before they starve. The researchers’ findings show that earlier optimism that increased carbon dioxide in the atmosphere would have a fertilization effect, allowing food plants to grow quicker in a warmer world, is more than countered by a loss in nutrition.
For an overcrowded world this could be disastrous.