Within the next 100 years, Earth as we know it could be transformed into an unrecognizable, alien world, with ecosystems around the globe falling apart. After looking at over 500 ancient climate records, scientists have said current climate change is comparable to what the planet went through when it came out of the last ice age – and the seismic shift in biodiversity that took place then will likely happen again.
At the end of the Last Glacial Maximum, when ice sheets covered most of North America, Asia and northern Europe, the planet warmed up by between four and seven degrees Celsius. Over the course of 10,000 years, the ice melted and entirely new ecosystems emerged, eventually developing into what we see today.
Climate scientists are currently predicting that if greenhouse gas emissions continue at their current rate (the so-called “business as usual” scenario) then the planet will have warmed around four degrees Celsius by 2100.
In a study published in Science, an international team of researchers looked at hundreds of paleontological records, examining how terrestrial ecosystems responded to climate change 20,000 years ago in a bid to establish how the planet might adjust to similar warming in the next 100 to 150 years. They looked at potential changes using different climate scenarios – from warming being limited to 1.5 degrees Celsius through to business-as-usual.
Findings showed that unless there are huge reductions in greenhouse gas emissions, terrestrial ecosystems around the world are at risk of “major transformation,” with most of these changes taking place over the next 100 years.
“Terrestrial vegetation over the entire planet is at substantial risk of major compositional and structural changes in the absence of markedly reduced [greenhouse gas] emissions,” they wrote. “Much of this change could occur during the 21st century, especially where vegetation disturbance is accelerated or amplified by human impacts. Many emerging ecosystems will be novel in composition, structure and function, and many will be ephemeral under sustained climate change; equilibrium states may not be attained until the 22nd century or beyond.”
Study co-author Jonathan Overpeck, from the University of Michigan, said there will be a huge ricochet effect that will eventually threaten water and food security. “If we allow climate change to go unchecked, the vegetation of this planet is going to look completely different than it does today, and that means a huge risk to the diversity of the planet,” he said in a statement.
“We’re talking about global landscape change that is ubiquitous and dramatic, and we’re already starting to see it in the United States, as well as around the globe. Our study provides yet another wake-up call that we need to act now to move rapidly towards an emission-free global economy.”