As world leaders head to the United Nations Climate Change Conference next week, climate targets will be put under the microscope. But some scientists say greater attention should be placed on the role of animals in controlling the carbon cycle - suggesting the introduction of even a targeted group of species to some ecosystems could be enough to keep global temperatures below the 1.5 degree Celsius tipping point. It's a conservation process called 'Rewilding' - which involves re-patriating wildlife to damaged ecosystems - and allowing nature to 'bounce back.'