Climate change is profoundly shaping the planet, its ecosystems, and the creatures that inhabit them. A recent international study confirms a striking consequence: lizards appear to be born physiologically older as temperatures rise. This early aging threatens their ability to reach reproductive maturity, raising concerns about the survival of affected populations.
Cellular energy production and growth drive aging in all animals. When global temperatures climb, the natural aging process can accelerate. The French central highlands were the focus of a study examining how heat impacts the DNA of lizard populations, providing evidence that climate warming may hasten aging at the cellular level.
The research, published in Proceedings of the National Academy of Sciences, describes accelerated aging as a response to climate-induced population declines in central France. It notes an intergenerational buildup of telomere shortening, meaning pups are effectively born old. This trend appears to intensify across generations, contributing to a population aging cycle.
By testing DNA from lizards of various ages, the scientists measured telomere length. Telomeres cap chromosomes and reveal overall health and the aging pace of the organism. The data indicate that heat stress experienced by mothers can yield offspring with damaged and aged DNA, a condition that can be passed down and threaten species continuity.
damaged and old DNA
Findings show temperatures have risen to levels where many pups inherit short telomeres from mothers affected by heat stress. This inheritance pattern suggests a physiological aging baseline present at birth, reducing the likelihood of reaching reproductive age.
In the study, researchers emphasize that biodiversity is facing a global crisis with rapid species loss that is accelerating under warming. The risks are especially high for limited-range or cold-adapted species, which may struggle to cope with changing conditions.
A key challenge highlighted is the limited understanding of the mechanisms linking warmer climates to life history shifts and the early signs of warming-related extinctions. The research underscores the need to map how climate affects birth intervals, reproduction timing, and lifespan—not just in lizards, but across vertebrates and other life forms.
Some notable results show that climate warming can adjust the interval between birth, first reproduction, and death. This shift, already observed in lizards, could occur in other animals and potentially humans. Conversely, cooler body temperatures often extend lifespan in both warm-blooded and cold-blooded species.
live fast die young
In terrestrial ectotherms, rising temperatures can constrain activity, raise maintenance costs, and increase heat-stress risks. Over time, these factors may reshape life history strategies on the slow-fast continuum and alter how energy and resources are allocated within populations.
Scientists have revisited this topic before. An earlier international study, with researchers from the CSIC, found that lizards from colder climates are particularly sensitive to warming trends, underscoring the uneven impact of heat across species and regions.
The ongoing nature of this inquiry is illustrated by a recent Nature Communications publication that links reduced humidity from warming to environments that some lizard species cannot endure. Lizards adapted to tropical climates facing temperate zones are especially vulnerable to heat increases, with physiology tightly tied to ambient temperatures.
Among the diversity of lizards, some survive desert habitats while others inhabit cold, high-altitude regions. There are also species adapted to northern ranges, extending towards the Arctic Circle. The study speculates that lizards in Mediterranean mountain regions, including the Iberian Peninsula where warming is expected to be most intense, may experience range contractions and heightened competition from more adaptable species. This outcome could threaten endemic lizards such as Lacerta schreiberi, a concern noted by CSIC at the time.
Reference note: PNAS article DOI: 10.1073/pnas.2201371119. This work contributes to a growing body of evidence on how climate change shapes life histories and genetic aging in reptiles and other animals.
For those seeking more detail, scientists emphasize that ongoing observation and broader geographic studies are essential to understand how widespread these aging patterns are and what they mean for conservation strategies in North America and beyond.
Note: The study and findings are attributed to a consortium of researchers across international institutions, with findings summarized in the cited publications and institutional reports. Additional information is provided by the involved research teams with formal attributions to the journals noted above.