New research is predicting the mass extinction of many species if the planet’s temperature rises by 6°C. With food supplies drastically reduced in such a climate, dwarfism is likely to result among humans as an evolutionary strategy to avoid starvation.

This forecast is based on historical evidence that points to a similar scenario when the world’s temperature last rose by 6°C.

Under the Bighorn Basin Coring Project, an international group of 30 scientists have studied vast fossil deposits in rock strata in Wyoming in the US, charting the period 55 million years ago when the Earth’s temperature rose suddenly – as it is expected to do this century.

On that occasion it took 10,000 years for the temperature to rise by 6°C. While there were mass extinctions, the timescale gave some plants and animals time to adapt and migrate to survive.

Many species such as horses, insects and earthworms evolved quickly – dwarfism being one of the most widespread and successful strategies.

However this current warming period could take as little as 200 years, according to predictions from the Intergovernmental Panel on Climate Change. Scientists say this would allow no time for many long-lived species, such as trees, to evolve and migrate.

Mammals would also struggle to move to new areas due to industrialisation and agricultural development. As mass extinction results, surviving species will end up competing for diminishing and less nutritious food supplies.

The findings also pour cold water on earlier optimism that increased carbon dioxide in the atmosphere would have a fertilisation effect for food plants, as this would be more than countered by a loss in nutrition.

According to University of Birmingham research fellow Dr Phillip Jardine, one of the scientists involved in the project, the impacts of altering the global carbon balance could be catashropic for an over-populated world.

Speaking to Climate News Network, he said: “Even if future climate change isn’t a convincing enough argument to decrease carbon emissions, increasing atmospheric CO2 concentrations has a very real possibility of reducing the viability of our own food supplies, by compromising the base of the food chain for ourselves and the animals that we farm and eat.

“If we acknowledge the presence of increasing temperatures then we have an additional factor that we would expect to decrease further the size of our farmed animals, and thus the amount of food that we can take from them.”

Maxine Perella

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