A simplified ecological landscape—with substantial biodiversity loss—might be the output result if a global temperature increase does not remain at 1.5 ?C above historical pre-industrial levels.

Currently, our planet's temperature increases by 2 ?C, has taken the world into a temperature state that it hasn't seen in several million years. This is in response to a report from the Tyndall Centre for Climate Change Research at the University of East Anglia in the United Kingdom. It showed that unless the global temperature increase is not limited to 1.5 degrees C, but is allowed to rise with 2 degrees C, it roughly doubles the risks associated with warming for plants, animals and insects.

Even though many countries set pledges towards limiting climate change, scientists predict a corresponding warming of about 3.2 degrees C. If this happens, we could see 47 % of insect species, 26 % of vertebrate and 16 % of plant species standing to lose at least half of their geographic ranges.

What does this all mean? Well it would mean that high levels of warming will bring forth  Systemic Ecological Simplification, a process where many "climate losers" are replaced by far fewer "climate winners." Such a simplified ecological landscape could have impacts on ecosystem services such as water quality, soil conservation, flood prevention, all of which are important for human well-being. Fewer insects also mean fewer pollinators and hence concomitant implications for many plant species, and related food production.

But even if governments and industry manage to limit warming to 1.5 degrees C, recent research shows that large hectares of land would have to be made available for capturing and storing carbon. Some estimates are for up to 18 percent of the land surface or 24-36 percent of current arable cropland by the end of this century.

Either way, biodiversity may get the worst end of the bargain, because the expanding land use itself could threaten remaining habitats. So in essence, the only way we can  stay as close to 1.5 degrees as possible is by damaging many of the habitats that support biodiversity in order to achieve a target that will save biodiversity. Which is quite ironic.

There is a dire need to find the combination of options that minimise battle between these competing demands. If success is found in solving the nexus between climate security, land use and biodiversity conservation, will the assurance of a sustainable future in the long-term be plausible.

References:

Reference-webpage: https://phys.org/news/2018-05-biodiversity-climate.html

 "Narrowing pathways to a sustainable future," by G. Midgley, Science (2018). science.sciencemag.org/cgi/doi ? 1126/science.aat6671

"The projected effect on insects, vertebrates, and plants of limiting global warming to 1.5?C rather than 2?C," R. Warren el al., Science (2018). science.sciencemag.org/cgi/doi ? 1126/science.aar3646 

 Read more at: https://phys.org/news/2018-05-biodiversity-climate.html#jCp