“We are pushing the ecosystems … out of the environment in which they evolved ‘
By Summit Voice
FRISCO — Starting with the tropics, many locations on Earth will start to see new climate normals within the next few decades — Kingston, Jamaica could reach that point within the next decade, and other well-known cities, including Singapore, Mexico City and Phoenix will see off-the-chart temperatures by mid-century, according to climate scientists and geographers with the University of Hawaii, Manoa.
Their study, published Oct. 10 in Nature, creates an index of the year when the mean climate of any given location on Earth will shift continuously outside the most extreme records experienced in the past 150 years.
The index used the minimum and maximum temperatures from 1860-2005 to define the bounds of historical climate variability at any given location. The scientists then took projections for the next 100 years to identify the year in which the future temperature at any given location on Earth will shift completely outside the limits of historical precedents, defining that year as the year of climate departure.
“The results shocked us. Regardless of the scenario, changes will be coming soon,” said lead author Camilo Mora. “Within my generation, whatever climate we were used to will be a thing of the past.”
The new index shows surprising results. Areas in the tropics are projected to experience unprecedented climates first. That will drive impacts to biodiversity through small but rapid climate changes in the Earth’s warmest regions, since tropical species are unaccustomed to climate variability and are therefore more vulnerable to relatively small changes.
And already, ocean acidity has entered the realm of a new normal, outside the bounds of natural variability, according to the study.
“This work demonstrates that we are pushing the ecosystems of the world out of the environment in which they evolved into wholly new conditions that they may not be able to cope with. Extinctions are likely to result,” said Ken Caldeira of the Carnegie Institution for Science‘s Department of Global Ecology, who was not involved in this study. “Some ecosystems may be able to adapt, but for others, such as coral reefs, complete loss of not only individual species but their entire integrity is likely.”
Rapid change will tamper with the functioning of Earth’s biological systems, forcing species to either move in an attempt to track suitable climates, stay and try to adapt to the new climate, or go extinct.
These changes will affect our social systems as well. The impacts on the tropics have implications globally as they are home to most of the world’s population, contribute significantly to total food supplies, and house much of the world’s biodiversity.
“Our results suggest that countries first impacted by unprecedented climates are the ones with the least capacity to respond,” said coauthor Ryan Longman. “Ironically, these are the countries that are least responsible for climate change in the first place.”
In predominately developing countries, over one billion people under an optimistic scenario, and five billion under a business-as-usual-scenario, live in areas that will experience extreme climates before 2050. This raises concerns for changes in the supply of food and water, human health, wider spread of infectious diseases, heat stress, conflicts, and challenges to economies.
“This paper is unusually important. It builds on earlier work but brings the biological and human consequences into sharper focus,” said Jane Lubchenco, former Administrator of the National Oceanic and Atmospheric Administration and now of Oregon State University, who was not involved in this study. “It connects the dots between climate models and impacts to biodiversity in a stunningly fresh way, and it has sobering ramifications for species and people.”
“Scientists have repeatedly warned about climate change and its likely effects on biodiversity and people,” said Mora. “Our study shows that such changes are already upon us. These results should not be reason to give up. Rather, they should encourage us to reduce emissions and slow the rate of climate change. This can buy time for species, ecosystems, and ourselves to adapt to the coming changes.”