Recent observations show that a species has thrived despite extreme weather through rapid evolution. Does this suggest that species increasingly affected by soaring temperatures and challenging conditions can adapt as the planet continues to warm?

Historically, evolution has rescued numerous species from climate-related threats. Over the past 500 million years, Earth’s climate has fluctuated significantly, with species, including crocodiles, thriving in regions like the Arctic. Plants and animals have consistently adapted to survive as their environment changes.

The critical factor is time. Previously, the quickest climatic shift known was the Paleocene-Eocene Thermal Maximum, occurring approximately 56 million years ago, when temperatures jumped by 5 to 8 degrees Celsius over about 20,000 years. Today’s projections suggest temperatures could exceed 4°C by century’s end. Can evolution effect such rapid change?

The answer, particularly for organisms with short life cycles, is a resounding yes. Compelling evidence comes from the wild plant known as the Scarlet Monkeyflower (Mimulus cardinalis), which adapted rapidly during the drought that hit California from 2012 to 2015.

Daniel Anstedt, a researcher at Cornell University in New York, began an extensive study of the monkeyflower in 2010. He assessed the plants’ growth annually across many habitats and collected samples for DNA analysis.

The Scarlet Monkeyflower thrives near water, making it vulnerable to drought conditions. Anstedt notes, “If you plant it in a pot and don’t water it for a few days, it simply dies.”

Remarkably, while three local populations disappeared, many surviving plants exhibited numerous mutations related to climate adaptation in their genomes, indicating they evolved drought tolerance within a remarkable three years. These populations were also the fastest to recover post-drought.

This phenomenon is termed “evolutionary rescue,” where species survive critical threats through rapid evolutionary changes. While lab studies have demonstrated this, Anstedt asserts that this is the first real-world case of its kind.

“Demonstrating exponential evolution is challenging,” Anstedt explains. “It requires showing a population’s decline due to a threat, illustrating genetic adaptation, and confirming that these changes facilitated recovery.”

Numerous instances of evolutionary rescue exist; for example, finches in the Galápagos Islands adapted to drought, Tasmanian devils evolved in response to contagious cancer, pests gained resistance to pesticides, and killifish adapted to pollution in U.S. rivers. However, Anstedt notes that verifying all three key factors in these instances remains uncharted territory.

“This research is pivotal as it shows recovery can be attributed to rapid evolution, a realization that hasn’t been documented extensively across species,” he adds.

Andrew Stouffer, a professor at Washington State University studying Tasmanian devils, concurs: “While we’ve observed rapid evolution in species like the Tasmanian devil, evidence linking it to demographic recovery is scarce.”

It’s important to note that the three-year drought detailed here is weather-related, not necessarily indicative of long-term climate shifts. “Determining long-term adaptation to climate change requires additional time,” Stouffer emphasizes.

In essence, the Scarlet Monkeyflower’s adaptation to survive one severe drought doesn’t guarantee it can evolve to withstand rising temperatures or extreme weather variations a century or more down the line. “Future droughts could be even worse than those experienced recently,” Anstedt warns.

Moreover, as populations decline, valuable genetic diversity—the key to evolutionary adaptability—is lost. Frequent and severe population declines diminish a species’ evolutionary potential each time.

Consequently, as global warming escalates, the frequency and intensity of threats will likely increase, while the capacity for evolution may diminish, particularly in long-lived species with extended generation times.

Nevertheless, Anstedt views his findings as promising. “Many current predictions about species decline neglect to account for evolution,” he concludes. “This insight brings hope for future adaptability.”