Future of the human climate niche

Area of Science:

• Environmental science
• Human ecology
• Climate science

Background:

• Species occupy specific environmental niches.
• Human populations have historically inhabited a narrow climatic range.
• Technological advancements have not fundamentally altered human climatic preferences.

Purpose of the Study:

• To investigate the long-term human temperature niche.
• To analyze the impact of climate change on human habitation zones.
• To project future population exposure to altered climatic conditions.

Main Methods:

• Analysis of historical human population distribution data.
• Correlation of population density with mean annual temperature (MAT).
• Climate modeling under a business-as-usual scenario to project future niche shifts.

Main Results:

• Human populations have predominantly resided in areas with MAT between 11°C and 15°C for millennia.
• Current agriculture and economic output show a similar temperature optimum.
• Projected climate change will shift this niche significantly, potentially exposing one-third of the global population to extreme heat (>29°C) by 2070.
• Affected regions are often in poorer countries with low adaptive capacity.

Conclusions:

• Human populations are constrained by a narrow temperature niche, similar to other species.
• Climate change poses a significant threat to human habitability and development, particularly in vulnerable regions.
• Prioritizing human development in at-risk areas and climate change mitigation are crucial.