Towards a Future Threatened by Climate Change and Human Displacement
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Chapter 1: The Looming Crisis of Climate Migration
By the year 2100, projections suggest that approximately one-third of the global population may be compelled to abandon their native lands. Areas that were once rich and accommodating could turn inhospitable, pushing many to seek refuge elsewhere. While a fortunate minority may afford advanced technological adaptations, the majority will be forced to flee, creating an unprecedented wave of climate refugees. These individuals may find themselves wandering the globe, displaced from what was once a thriving environment, now rendered uninhabitable.
As of 2024, climate change, coupled with population growth, has already driven nearly 700 million people—about 9% of the world's population—into extreme heat conditions, according to research published in Nature Sustainability (Lenton et al., 2023). If current trajectories persist, a rise of 2.7 degrees Celsius could escalate this figure to 40%. By 2070, the global population is anticipated to reach 9.5 billion, primarily in already warm regions.
In a more favorable scenario, containing warming to 1.5 degrees would only affect 14% of the global populace. Preventing each additional 0.3-degree rise could shield roughly 350 million individuals from dire circumstances.
Section 1.1: Understanding Human Climate Limits
Climate change effects are frequently analyzed through an economic lens; however, these assessments can obscure the genuine repercussions, often portraying wealthier nations as more adversely affected due to higher financial losses. This study shifts the focus towards the direct effects of climate change on human welfare by establishing a concept known as the "human climate niche," which defines the temperature range conducive to human comfort.
Historical data reveals that for the past 6,000 years, humanity has prospered in regions with an annual average temperature of around 13 degrees Celsius (PNAS: Xu et al., 2020). A considerable segment of the global population has also thrived in monsoonal areas with average temperatures near 27 degrees Celsius, such as Southeast Asia.
However, once annual temperatures surpass 29 degrees Celsius, significant adverse effects emerge: mortality rates escalate, and many individuals may be compelled to vacate their homes. With temperatures exceeding this threshold, the frequency of days where prolonged outdoor activity becomes life-threatening increases. The combination of extreme heat and humidity severely impairs the body's ability to cool down, as indicated by the "wet-bulb temperature," with 28 degrees being a critical survival limit. These perilous conditions are already sporadically experienced in regions like Pakistan, and further warming could lead to more frequent and prolonged threats, complicating food production as well.
Experts not affiliated with the study warn that while the human climate niche is a useful construct, it cannot be precisely defined. Lisa Schipper, a lead author of the IPCC climate report, emphasized this point, stating that "no single metric can capture reality precisely, but the human climate niche concept is extremely helpful to think beyond numbers."
Section 1.2: Challenges to Agricultural Viability
Droughts and desertification could render the cultivation of grains, fruits, and vegetables unfeasible within the human climate niche, a phenomenon already observable in parts of the Mediterranean. Moreover, low-lying regions risk flooding due to rising sea levels, regardless of temperature conditions. Richard J.T. Klein from the Stockholm Environment Institute notes that "regions within the human climate niche could become uninhabitable for other reasons."
Chapter 2: The Potential for Technical Adaptation
Adaptation to increasingly hostile environments is feasible, according to Klein. "People can spend most of their time in air-conditioned spaces and import food, provided they can afford it." Nevertheless, in many vulnerable areas—such as critical hotspots in India, Nigeria, Indonesia, and countries like Burkina Faso, Mali, and Qatar—affordability may be a barrier, leaving vast expanses nearly unlivable.
In developed nations like Germany, most work occurs in climate-controlled environments. In contrast, many jobs in developing countries are outdoors, particularly in agriculture. Adjusting work schedules to include midday breaks could enhance safety, but maintaining full productivity remains a challenge, notes Christian Franzke of the IBS Center for Climate Physics at Pusan National University.
The first video titled "Adam Hart - Unfit for Purpose" delves into the implications of climate change on human life and the potential for future adaptation.
The second video, "Unfit for Purpose with Prof Adam Hart | NI Science Festival," explores the challenges of climate change and the urgency for effective solutions.
An Uncertain Future
The future actions of those impacted by severe climate conditions are unpredictable. It remains unclear who will leave their homes and where they will seek refuge amidst potential conflicts over dwindling resources. The Intergovernmental Panel on Climate Change (IPCC) has refrained from offering specific predictions regarding the number of individuals who may be displaced by climate change. However, development geographer Schipper highlights the likelihood of increased migration: "In areas where dignified living becomes virtually impossible, those with the means will likely seek to relocate."
In the upcoming decades, many individuals' homelands could become existential threats due to factors not limited to conflicts or poverty, as rising temperatures may render them uninhabitable. Once annual average temperatures exceed 29 degrees Celsius, extreme, life-threatening heat could become the norm, making outdoor activities increasingly hazardous.
Without significant innovations in cooling technologies, natural adaptation will become unfeasible. Last year, Germany's average annual temperature was 10.5 degrees, underscoring the severity of 29 degrees. Data suggests that with every degree of global warming, regions unsuitable for human habitation will expand dramatically. Currently, around 60 million people reside under such conditions. If temperatures rise by two degrees, this figure could surpass 800 million, and with a 1.5-degree increase projected by 2070, over 400 million individuals could be affected.
Countries in North Africa and the Arabian Peninsula stand to be severely impacted. If global warming reaches 3.6 degrees, vast areas of South America, significant portions of India, Southeast Asia, and northern Australia could become nearly uninhabitable.
Can Extreme Climate Render Regions Uninhabitable?
Not necessarily. Historically, humans have adapted to extreme climates more effectively than most species. For instance, ancient civilizations inhabited the Arctic Circle, enduring temperatures as low as minus 50 degrees, while contemporary technology enables habitation in Antarctica's frigid environment. Similarly, nomadic tribes in the Sahara have adapted to extreme heat and water scarcity.
However, these instances are exceptions. Traditionally, most people have preferred to inhabit areas with temperate climates, which are more conducive to agriculture, settlement, and trade—typically characterized by average annual temperatures around 13 degrees Celsius or, as in monsoonal Southeast Asia, about 27 degrees Celsius.
Richard Klein of the Stockholm Environment Institute emphasizes that the true impact of climate change lies in the direct human suffering it engenders, a reality this study vividly illustrates.
Projections of a Changing Future
Researchers have been investigating the evolving human climate niche, concentrating on temperature ranges suitable for comfortable living, as outlined in the journal Nature Sustainability (Lenton et al., 2023). While temperature data is informative, it cannot fully encompass all factors that might make a region uninhabitable. Predictions concerning future population movements remain uncertain, with current efforts aiming to estimate how many individuals might confront dangers from rising temperatures.
Tim Lenton, the study's lead author, states that their objective was to gauge the potential magnitude of existential threats stemming from increasing temperatures. The findings suggest that effective climate protection could prevent many people from facing severe conditions. However, with the ongoing trajectory of a 2.7-degree increase, more than 1,000 cities housing over 100,000 residents each could experience life-threatening heat. Even a mere 0.5-degree rise could double the number of affected individuals, leading to significant health and economic challenges, particularly in areas where outdoor work is prevalent and agriculture is difficult.
Richard Klein reiterates that the study underscores the direct human suffering caused by climate change. Urban areas, in particular, are likely to experience intensified heat due to the heat island effect. The urgency is evident: reversing this trend necessitates more than political or technical measures; it requires a fundamental change in lifestyle, moving away from the fallacies of endless growth and unsustainable consumption. However, the feasibility of such a transformation remains uncertain.