Humanity is ‘cutting down the tree of life’, warn scientists

Humanity’s ongoing annihilation of wildlife is cutting down the tree of life, including the branch we are sitting on, according to a stark new analysis.

More than 300 different mammal species have been eradicated by human activities. The new research calculates the total unique evolutionary history that has been lost as a result at a startling 2.5bn years.

Furthermore, even if the destruction of wild areas, poaching and pollution were ended within 50 years and extinction rates fell back to natural levels, it would still take 5-7 million years for the natural world to recover.

Many scientists think a sixth mass extinction of life on Earth has begun, propelled by human destruction of wildlife, and 83% of wild mammals have already gone. The new work puts this in the context of the evolution and extinction of species that occurred for billions of years before modern humans arrived.

The new research, published in the Proceedings of the National Academy of Sciences, did not simply add up the number of lost species, as this fails to capture how unique each species is in evolutionary terms.

The researchers added up the amount of time each lost species had spent evolving since it emerged, a measure called phylogenetic diversity. There are hundreds of species of shrew, for example, but just two species of elephant. Losing elephants would therefore be like chopping a large branch off the tree of life, said Davis, whereas losing a shrew species would be like trimming off a small twig.

From the rise of modern humans to the year 1500,2bn years of evolutionary history was lost due to mammal extinctions, the researchers calculated. Since 1500, another 500m years has been lost. If the current high rate of extinctions continues for 50 years, a further 1.8bn years of phylogenetic diversity will disappear, the scientists found.

There are still many mammal species left, but all of these would have to evolve for 5-7m years into the future to get back to the level of diversity present before modern humans arrived, the researchers estimated.

Fracking starts at landmark Lancashire site

Fracking for shale gas has begun for the first time in the UK since it was linked with earthquakes in 2011.

Energy firm Cuadrilla confirmed the controversial process had started at its site in Little Plumpton, Lancashire after a legal challenge failed on Friday.

Protester Ginette Evans said there was a "mood of disappointment" but insisted the fight was "not over".

Cuadrilla insisted the process was safe and would be of "enormous" benefit.

The company's chief executive Francis Egan said: "These are the first exploration wells that will be tested... we have high hopes for them but we have to wait and see what comes out."

If successful, he said it would "lead to tens of thousands of jobs and could be a very significant contributor to the exchequer and... could also reduce emissions because it will be better than importing gas from far afield".

What is fracking?

Fracking is the process of drilling down into the earth before a high-pressure water mixture is directed at the rock to release the gas inside.

Water, sand and chemicals are injected into the rock at high pressure which allows the gas to flow out to the head of the well.

The process can be carried out vertically or, more commonly, by drilling horizontally to the rock layer, which can create new pathways to release gas or used to extend existing channels.

The term fracking refers to how the rock is fractured apart by the high-pressure mixture.

Drilling for shale gas is still at an exploratory phase.

However, reserves of shale gas have been identified across large swathes of the UK, particularly in northern England.

More than 100 licences have been awarded by the government, allowing firms to pursue a range of oil and gas exploration activities in certain areas.

Before companies can begin fracking they must also receive planning permission from the relevant local council.

Cuadrilla faced legal challenges before it could begin drilling at its Preston New Road site at Little Plumpton in Lancashire.