Future of the human climate niche | PNAS

Xu, Chi, Timothy A. Kohler, Timothy M. Lenton, Jens-Christian Svenning, and Marten Scheffer. “Future of the human climate niche.” Proceedings of the National Academy of Sciences 117, no. 21 (2020): 11350-11355.

PDF of Article

Significance

We show that for thousands of years, humans have concentrated in a surprisingly narrow subset of Earth’s available climates, characterized by mean annual temperatures around ∼13 °C. This distribution likely reflects a human temperature niche related to fundamental constraints. We demonstrate that depending on scenarios of population growth and warming, over the coming 50 y, 1 to 3 billion people are projected to be left outside the climate conditions that have served humanity well over the past 6,000 y. Absent climate mitigation or migration, a substantial part of humanity will be exposed to mean annual temperatures warmer than nearly anywhere today.

Abstract

All species have an environmental niche, and despite technological advances, humans are unlikely to be an exception. Here, we demonstrate that for millennia, human populations have resided in the same narrow part of the climatic envelope available on the globe, characterized by a major mode around ∼11 °C to 15 °C mean annual temperature (MAT). Supporting the fundamental nature of this temperature niche, current production of crops and livestock is largely limited to the same conditions, and the same optimum has been found for agricultural and nonagricultural economic output of countries through analyses of year-to-year variation. We show that in a business-as-usual climate change scenario, the geographical position of this temperature niche is projected to shift more over the coming 50 y than it has moved since 6000 BP. Populations will not simply track the shifting climate, as adaptation in situ may address some of the challenges, and many other factors affect decisions to migrate. Nevertheless, in the absence of migration, one third of the global population is projected to experience a MAT >29 °C currently found in only 0.8% of the Earth’s land surface, mostly concentrated in the Sahara. As the potentially most affected regions are among the poorest in the world, where adaptive capacity is low, enhancing human development in those areas should be a priority alongside climate mitigation.

• climate
• migration
• societies

Global warming will affect ecosystems as well as human health, livelihoods, food security, water supply, and economic growth in many ways (1, 2). The impacts are projected to increase steeply with the degree of warming. For instance, warming to 2 °C, compared with 1.5 °C, is estimated to increase the number of people exposed to climate-related risks and poverty by up to several hundred million by 2050. It remains difficult, however, to foresee the human impacts of the complex interplay of mechanisms driven by warming (1, 3). Much of the impact on human well-being will depend on societal responses. There are often options for local adaptations that could ameliorate effects, given enough resources (4). At the same time, while some regions may face declining conditions for human thriving, conditions in other places will improve. Therefore, despite the formidable psychological, social, and political barriers to migration, a change in the geographical distribution of human populations and agricultural production is another likely part of the spontaneous or managed adaptive response of humanity to a changing climate (5). Clearly there is a need to understand the climatic conditions needed for human thriving. Despite a long and turbulent history of studies on the role of climate, and environment at large, on society in geography and beyond (6), causal links have remained difficult to establish, and deterministic claims largely refuted, given the complexities of the relationships in question (7). Rather than reentering the murky waters of environmental determinism (8, 9), here we take a fresh look at this complex and contentious issue. We mine the massive sets of demographic, land use, and climate information that have become available in recent years to ask what the climatic conditions for human life have been across the past millennia, and then examine where those conditions are projected to occur in the future.

…(read more).

Welcome to the End of the ‘Human Climate Niche’

By David Wallace-Wells

On Wednesday, a “super cyclone,” now the equivalent of a Category 5 hurricane, is expected to make landfall on the border of India and Bangladesh. The storm will weaken as it approaches land, but in India, it is already forcing evacuations in the thousands just as the country has begun easing its coronavirus lockdown, the world’s largest. In Bangladesh, Earther reports, “the super cyclone is expected to cause heavy precipitation and flooding in the Cox’s Bazar refugee camps, which house more than a million refugees from the Rohingya crisis and are already flood-prone.”

It has become commonplace to say that the coronavirus pandemic is the latest preview of the climate-change future. We have been shown repeatedly, and yet do not learn, that we live within nature, subject to its laws and limits and brutality, and that many of the fortresslike features of modern life that we once assumed were unshakable and unmovable turn out to be very fragile and vulnerable indeed. But it is not just metaphorically true that the pandemic is showing us a preview of the climate-change future, it is also literally true, because the global economic slowdown has meant a reduction of air pollution, which, in general, cools the planet by reflecting sunlight back into space — perhaps, in total, by as much as a half-degree or even full degree Celsius. Less air pollution means, as a result, warmer temperatures. And though the decline in pollution produced by the coronavirus is not total (meaning we won’t be leaping forward a full degree of warming this year), the reduction may well be enough to make 2020 the warmest year on record and produce a summer defined by extreme heat. In other words, we will be living through climate conditions we wouldn’t have otherwise encountered for at least a few more years — living through something like the summer of 2025 in 2020.

We will be facing other extreme events too. Here in the United States, hurricane season is about to begin — an unusually intense one is expected, perhaps even record-breaking, with scientists predicting that there is a 70 percent chance that a major hurricane strikes the continental U.S., which will almost certainly be handling evacuations and precautions in the midst of continued social distancing. (The hurricane season has gotten going early this year, with a named tropical storm appearing before the official onset of hurricane season for the sixth year in a row). And then there’s wildfire season.

In my book, The Uninhabitable Earth, I called the threat of simultaneous or successive disasters like these “climate cascades” — each making it harder to respond to the next. In California, Governor Gavin Newsom has worried that the states’ coronavirus prison furloughs, intended to reduce the risk of coronavirus spreading within prisons, may undermine its ability to fight wildfires this season, since a large share of the states’ firefighters are actually prisoners facing down flames for as little as $1 a day. Usually, they are outfitted for protection with N95 respirator masks. This season, those will almost certainly be in short supply as well. We tend to think of climate impacts as discrete threats: a wildfire, a hurricane, a drought. By the year 2100, it’s possible that parts of the planet will be hit by six climate-driven natural disasters at once. Wildfires tearing through communities cowering terrified by a rolling pandemic only counts as two.

This is what it means to be living already outside the “human niche.” The term comes from a landmark paper published late last month in the Proceedings of the National Academy of the Sciences, “Future of the Human Climate Niche.” What do the authors mean by it? In short, that the range of temperatures that make human flourishing possible is quite narrow, and that climate change promises to close that window — not entirely, but enough to meaningfully diminish how much of the planet can support prosperous, comfortable life.

…(read more).

Climate change could bring near-unliveable conditions for 3bn people, say scientists | Financial Times

https://www.ft.com/content/072b5c87-7330-459b-a947-be6767a1099d

https://www.ft.com/content/072b5c87-7330-459b-a947-be6767a1099d

Each degree of warming above present levels corresponds to roughly 1bn people falling outside of ‘climate niche’

Steven Bernard, Dan Clark and Sam Joiner November 1 2021

Map animation showing human climate niche, the suitability of for habitation. In 2020, 0.8% of the earth’s surface had a mean annual temperature (MAT) of 29C or more, and was home to 29m people. By 2070, 19% of the earth’s surface will have an MAT of at least 29C, affecting up to 3bn people

Up to 3bn out of the projected world population of about 9bn could be exposed to temperatures on a par with the hottest parts of the Sahara by 2070, according to research by scientists from China, US and Europe.

However, rapid reductions in greenhouse gas emissions could halve the number of people exposed to such hot conditions. “The good news is that these impacts can be greatly reduced if humanity succeeds in curbing global warming,” said study co-author Tim Lenton, climate specialist and director of the Global Systems Institute at Exeter university.

The report highlights how the majority of humans live in a very narrow mean annual temperature band of 11C-15C (52F-59F). Researchers noted that despite all innovations and migrations, people had mostly lived in these climate conditions for several thousand years.

“This strikingly constant climate niche likely represents fundamental constraints on what humans need to survive and thrive,” said Professor Marten Scheffer of Wageningen University, who co-ordinated the research with his Chinese colleague Chi Xu, of Nanjing University.

Global warming has resulted in a 1.1C rise in temperatures since pre-industrial times, according to scientists. This is expected to reach 1.5C within 20 years, even in the best-case scenario of deep cuts in greenhouse gas emissions.

“Each degree of warming above present levels corresponds to roughly 1bn people falling outside of the climate niche,” Lenton noted.

At present, only 0.8 per cent of the global land surface experiences mean annual temperatures greater than 29C (84.2F).

If emissions continue to rise, this could spread to 19 per cent of the planet’s land area by 2070, under the worst-case scenario set out by the Intergovernmental Panel on Climate Change, the UN scientific body.
What are the scenarios?

Three different climate scenarios and three population projections are set down by the IPCC in its landmark report assessing climate change (see table below).

To visualise how liveable the earth will be in 2070 under these scenarios, the Financial Times has paired the population projections with each climate model and mapped them across six continents.

Issue 20 Archives – Fair World Project

Fair World Project (FWP) educates and advocates for a just global economy where: people are treated fairly with dignity; the environment is respected and nourished; commerce fosters sustainable livelihoods and communities in a global society based on cooperation and solidarity; fair market opportunities and fair government and trade policy defend, and support the contributions of farmers, workers, and artisans to our global society; marketing claims have integrity and promote throughout entire supply chains, and support dedicated brands that put people before profits.

The End of Alzheimer’s: The First Program to Prevent and Reverse Cognitive Decline: Dale E. Bredesen

A groundbreaking plan to prevent and reverse Alzheimer’s Disease that fundamentally changes how we understand cognitive decline.

Everyone knows someone who has survived cancer, but until now no one knows anyone who has survived Alzheimer’s Disease.

In this paradigm shifting book, Dale Bredesen, MD, offers real hope to anyone looking to prevent and even reverse Alzheimer’s Disease and cognitive decline. Revealing that AD is not one condition, as it is currently treated, but three, The End of Alzheimer’s outlines 36 metabolic factors (micronutrients, hormone levels, sleep) that can trigger “downsizing” in the brain. The protocol shows us how to rebalance these factors using lifestyle modifications like taking B12, eliminating gluten, or improving oral hygiene.

The results are impressive. Of the first ten patients on the protocol, nine displayed significant improvement with 3-6 months; since then the protocol has yielded similar results with hundreds more. Now, The End of Alzheimer’s brings new hope to a broad audience of patients, caregivers, physicians, and treatment centers with a fascinating look inside the science and a complete step-by-step plan that fundamentally changes how we treat and even think about AD.

For more information, including articles and diagrams, please visit Drbredesen.com or mpicognition.com.

Review

“Alzheimer’s is a disease for which there is no cure. Dr. Bredesen’s experimental program gives me hope that there are actions we can all take to care for our brains and keep Alzheimer’s at bay.”
—Maria Shriver, Today Show

“The End of Alzheimer’s is a monumental work. Dr. Bredesen completely recontextualizes this devastating condition away from a mysterious and unsolvable process to one that is both preventable and, yes, reversible. Pinning our hopes on pharmaceutical research to develop a miraculous wonder drug has left both physicians and patients empty handed. But now, this comprehensive approach offers solid results, bringing hope to so many.”
—David Perlmutter, MD, Board-certified neurologist and author, #1 New York Times bestseller, Grain Brain, and Brain Maker

“The End of Alzheimer’s, for the first time, synthesizes the latest science into a practical plan that can reverse Alzheimer’s and dramatically improve brain health and function. If you have a brain, read this book.”
—Mark Hyman, MD, author of the #1 New York Times bestseller Eat Fat, Get Thin

“This book represents a major turning point in our approach to Alzheimer’s disease, from viewing it as a mysterious and incurable affliction that is governed almost exclusively by our genes, to understanding it as a multifactorial condition that can be prevented and even reversed largely through nutrition and lifestyle change. For the first time ever, patients and families affected by Alzheimer’s—as well as those at high risk for this devastating disease—truly have a reason to be hopeful.”
—Chris Kresser, M.S., L.Ac Founder, Kresser Institute for Functional & Evolutionary Medicine, Author of the New York Times best seller The Paleo Cure

“The End of Alzheimer’s is a masterful, authoritative, and ultimately hopeful patient guide to functional medicine for your brain. It will help you prevent and reverse Alzheimer’s disease, whether you have the ApoE4 gene or not. My patients fear Alzheimer’s more than any other diagnosis. This is the book to transmute fear into action.”
—Sara Gottfried, MD, New York Times bestselling author of Younger

“Having spent several years implementing many of Dr. Bredesen’s insights in my patients, I can assure you that following his advice can save yourself, your loved ones, and your friends from suffering from this preventable and reversible curse.”
—Steven Gundry, MD, author of the New York Times bestseller The Plant Paradox

“Dr. Dale Bredesen is a world class neuroscientist/neurologist who through his innovative and exacting research has discovered a safe and effective approach to the prevention and treatment of Alzheimer’s disease that will revolutionize the way we think about the disease.”
—Jeffrey Bland, PhD, FACN, FACB; President, Personalized Lifestyle Medicine Institute

“The End of Alzheimer’s offers a new beginning in Medicine — changing the focus from a singular disease to recognizing the systems-based approach required to care for the whole person. Dr. Bredesen translates the knowledge of science to the wisdom that helps to heal our people . . . and provide a vision for the end of Alzheimers!”
—Patrick Hanaway, MD, Founding Medical Director, Director of Research, Center for Functional Medicine, Cleveland Clinic

“In this engaging, heartfelt, and insightful book, Dr. Bredesen elucidates a bold new approach to Alzheimer’s, rooted in decades of his own pioneering research. A must read for anyone wondering what can be done for this dread disease, whether for themselves, a loved one, or a patient.“
—Nathan Price, PhD, Professor & Associate Director of the Institute for Systems Biology

About the Author

Dale Bredesen, M.D., is internationally recognized as an expert in the mechanisms of neurodegenerative diseases such as Alzheimer’s disease. He graduated from Caltech, then earned his M.D. from Duke University Medical Center in Durham, North Carolina. He served as chief resident in neurology at the University of California, San Francisco (UCSF) before joining Nobel laureate Stanley Prusiner’s laboratory at UCSF as an NIH postdoctoral fellow. He held faculty positions at UCSF, UCLA, and the University of California, San Diego. Dr. Bredesen directed the Program on Aging at the Burnham Institute before coming to the Buck Institute in 1998 as its founding president and CEO. He is the chief medical officer of MPI Cognition.

• Publisher ‏ : ‎ Penguin Audio; Unabridged edition (August 22, 2017)
• Language ‏ : ‎ English
• ISBN-10 ‏ : ‎ 1524779199
• ISBN-13 ‏ : ‎ 978-1524779191
• Item Weight ‏ : ‎ 8.3 ounces
• Dimensions ‏ : ‎ 5.09 x 1.11 x 5.82 inches

Democracy Now! Top U.S. & World Headlines — November 15 2021

Democracy Now! – Nov 15, 2021

Glasgow Pact Slammed for Betraying the Global Poor Who Suffer Most from the Climate Emergency

15 Nov 2021
The U.N. climate summit in Glasgow, Scotland, ended Saturday with over 190 nations agreeing to the Glasgow Climate Pact, which calls on governments to return next year in Egypt with stronger plans to curb their emissions and urges wealthy nations to provide more funds to vulnerable countries in the Global South. It also pushes countries to phase out fossil fuel subsidies and reduce the use of coal, but activists say the final language of the agreement is too weak to meaningfully reduce emissions and limit global heating to 1.5 degrees Celsius, which scientists say is needed in order to avoid the most catastrophic consequences of the climate crisis. “There has been no real progress,” says Mitzi Jonelle Tan, a youth climate justice activist from the Philippines. “Once again, the U.N. climate summit just prioritized the voices of the privileged and not those that are most affected by the climate crisis.” We also speak with Brandon Wu, director of policy and campaigns at ActionAid USA, who says rich countries are scapegoating India and China for blocking stronger action on phasing out fossil fuels, while still growing their own oil and gas projects. “The real climate criminals are the wealthy countries,” says Wu.

“Hell on Earth”: Millions of Afghans Face Starvation as U.S. & West Freeze Billions in Gov ’t Funds

16 Nov 2021

Humanitarian and economic conditions are rapidly deteriorating in Afghanistan, where the U.N. estimates that more than half of the population suffers from acute hunger. The country has fallen into an economic crisis after the U.S. and other Western countries cut off direct financial assistance to the government following the Taliban takeover in August. Taliban leaders are also unable to access billions of dollars in Afghan national reserves that are held in banks overseas. “Forty million civilians were left behind when the NATO countries went for the door in August,” says Jan Egeland, secretary general of the Norwegian Refugee Council, who recently visited Afghanistan and with refugees in Iran, where as many as 5,000 Afghans are fleeing everyday. “They told me very clearly, ‘We believe we will starve and freeze to death this harsh winter unless there is an enormous aid operation coming through.’”

Historian Alfred McCoy Predicts the U.S. Empire is Collapsing as China’s Power Grows

16 Nov 2021
President Joe Biden’s virtual summit Monday with Chinese President Xi Jinping follows the two countries’ announcement just days earlier they will work together to confront the climate emergency after Xi did not attend the U.N. climate summit in Glasgow. Tension has been mounting between the two superpowers, especially over Taiwan and Hong Kong, with some speculating that a new Cold War is developing. “The United States, in the immediate future, is faced with the possibility of fighting a war over Taiwan … that it would probably lose,” says Alfred McCoy, professor of history at the University of Wisconsin-Madison in an extended interview about U.S.-China relations. “China is also working to break the U.S. geopolitical hold over the Eurasian landmass.” McCoy is a prolific author and his newest book is out today: “To Govern the Globe: World Orders and Catastrophic Change.”

BBC World Service – Newshour, President Biden and Xi Jinping hold virtual summit

President Biden and China’s leader, Xi Jinping, have held an extensive video summit that contained moments of warmth — but also warnings. We hear from Beijing and Washington DC.

Also in the programme: Russia destroys a satellite; and an interview with the Myanmar military.

Picture: A screen shows Chinese President Xi Jinping attending a virtual meeting with U.S. President Joe Biden via video link, at a restaurant in Beijing. Credit: Reuters)