New Insights Into Tropical Land Warming: Lessons from Millions of Years Ago
A groundbreaking study spearheaded by researchers from the University of Colorado Boulder unveils compelling evidence that tropical land regions may warm at rates significantly higher than previously anticipated, advancing crucial understanding of future climate change impacts. By investigating ancient lake sediment cores extracted from the Colombian Andes, this research sheds light on how tropical terrestrial temperatures responded to elevated carbon dioxide levels comparable to today’s atmosphere millions of years ago.
The findings unfold from a meticulous analysis of sediment cores drilled from the Bogotá basin, located nearly 2,550 meters above sea level within the tropical Andes. This unique sediment archive has been preserved virtually undisturbed since the late Pliocene epoch, approximately 2.5 to 5 million years ago—a geological window when Earth’s climate mirrored present-day carbon dioxide concentrations. Unlike ocean cores, which have traditionally dominated paleoclimate research due to their stability and continuity, this rare terrestrial record provides an unprecedented opportunity to scrutinize land temperature dynamics in the tropics during a warm interval of Earth’s history.
The research team employed advanced biochemical proxies, specifically bacterial membrane lipids known as branched glycerol dialkyl glycerol tetraethers (brGDGTs), to reconstruct a detailed temperature timeline spanning the Pliocene through the Pleistocene. These molecular fossils, preserved within the sediment layers, acted as reliable thermometers, enabling precise estimations of past mean annual temperatures in this critical equatorial region. This methodological innovation marks a significant leap forward in terrestrial paleoclimate reconstructions, allowing climate scientists to decipher temperature trends within terrestrial ecosystems that have long remained elusive.
Their analyses reveal a striking divergence between tropical land and ocean warming during the Pliocene period. Results indicate that terrestrial temperatures in the studied Andean region were approximately 3.7 °C (6.6 °F) higher than current levels, whereas adjacent tropical sea surface temperatures increased by a more modest 1.9 °C (3.4 °F). This twofold amplification of terrestrial warming relative to oceanic warming challenges conventional assumptions that land and sea temperatures would rise more synchronously in response to increasing greenhouse gas concentrations. Instead, it underscores the importance of land surface processes and feedback mechanisms that may drive pronounced thermal anomalies in tropical continental interiors under climate forcing.
Crucially, the study contextualizes these findings within the broader climate system dynamics of the late Pliocene, a time characterized by near-permanent El Niño–Southern Oscillation (ENSO) conditions in the Pacific Ocean. Persistent El Niño-like states likely exacerbated regional warming in the tropical Andes by altering atmospheric circulation patterns and reducing precipitation, thereby amplifying heat accumulation over land. This historical precedent signals potential parallels to contemporary climate scenarios where increasing greenhouse gas concentrations may similarly intensify ENSO variability, with profound implications for tropical land climate extremes.
Current observations already document how modern El Niño events precipitate significant warming and drought episodes across the northern Andes, threatening biodiversity and human livelihoods. Given climate model projections suggesting heightened frequency and intensity of El Niño events by mid-century, the insights drawn from this deep-time record accentuate the urgency of preparing tropical regions for greater thermal stress and hydrological disruption. Enhanced warming in these areas may push ecosystems and societies beyond critical thresholds, intensifying vulnerability to climate-induced hazards.
The study’s emphasis on tropical land surfaces addresses a fundamental gap in climate science. Historically, much research has gravitated towards high latitude polar regions or oceanic systems, largely because of the availability and continuity of data records from these locales. However, the tropics harbor nearly 40% of the global population and a staggering wealth of biodiversity, yet receive comparatively less scientific focus. Recognizing the disproportionate degree to which tropical land temperatures may rise relative to adjacent oceans has profound ramifications for climate adaptation strategies tailored to equatorial nations, most of which have limited economic resources to mitigate or adapt to rapid warming.
Furthermore, the investigation highlights the intricate cascade of feedback mechanisms embedded in the climate system. As one threshold is crossed—such as the permanent expansion of El Niño conditions or intensified land-atmosphere interactions—this may trigger cascading events magnifying regional warming. Such nonlinear responses complicate climate predictions and necessitate refined models capable of incorporating complex feedback loops within tropical terrestrial environments to inform more accurate future climate scenarios.
The utilization of geochemical proxies in fossil bacterial lipids as climate archives exemplifies the cutting-edge analytical approaches propelling climate science forward. By extracting and decoding the molecular signatures locked within sediments, researchers can transcend the limitations of historical instrument records and better understand how Earth’s complex climate system has behaved in past warm states. This knowledge not only enriches paleoclimatology but also serves as an essential empirical baseline to validate and calibrate computational climate models projecting 21st-century and beyond scenarios.
In painting a nuanced picture of tropical land climate sensitivity during the Pliocene, this study accentuates how future warming may not be a uniform, monolithic process but rather characterized by amplified heterogeneity and regional extremes. Expanding this line of research to integrate other tropical basins and complement with high-resolution climate modeling will be pivotal in constructing a comprehensive understanding of how vulnerable tropical terrestrial ecosystems and human communities will fare in an era of rapid anthropogenic warming.
Ultimately, the meticulous work led by Lina Pérez-Angel and colleagues serves as an urgent call to elevate tropical land regions within the global climate discourse. By bridging ancient climate records with the realities confronting millions of people today, their findings underscore the critical necessity of developing localized climate adaptation and mitigation frameworks. As warming pressures mount, tropical regions must no longer be relegated to the periphery of climate research and policy priorities but embraced as central to safeguarding planetary and human resilience.
The convergence of paleoclimate evidence, contemporary observation, and future climate projections illuminates a stark reality: tropical land temperatures will likely rise more sharply than once thought, carrying profound repercussions for ecosystems, water resources, agriculture, and the well-being of billions. This pioneering research not only reshapes the scientific community’s understanding of climate sensitivity but also equips societies with deeper knowledge critical to confronting the planet’s warming trajectory.
Subject of Research: Tropical land warming during the Pliocene epoch and implications for future climate change
Article Title: (Not explicitly provided)
News Publication Date: 2-Feb-2026
Web References: DOI: 10.1073/pnas.2520191123
Image Credits: Maria Fernanda Almanza
Keywords: Tropical warming, Pliocene climate, sediment cores, paleoclimate reconstruction, branched GDGTs, Colombian Andes, El Niño, climate feedbacks, terrestrial temperature amplification, climate adaptation, paleoclimate proxies, tropical ecosystems
