Recent scientific inquiry into the Amazon basin has revealed a significant transformation within the ecosystem, indicating a progression towards a ‘hypertropical’ paradigm as arid periods become more prolonged, intense, and recurrent.
These evolving climatic conditions have “no current analogue,” according to the global consortium of scientists who conducted this research. The botanical inhabitants are experiencing unprecedented levels of environmental strain, concurrently diminishing the Amazon’s capacity for atmospheric carbon sequestration.
Such is the magnitude of the current and projected environmental shifts, extrapolated from observational data spanning over three decades across the Amazon region, that the research cohort has established a novel classification: ‘hypertropical’. This designation refers to environmental states not witnessed on Earth for millennia.
The investigative team examined the adaptive responses of arboreal species and their subterranean root systems to episodes characterized by elevated thermal readings and water scarcity. As these phenomena intensify, they offer a concise preview of potential future conditions within the upcoming century.
“When these arid, high-temperature events manifest, that constitutes the climate we associate with a hypertropical forest, as it transcends the established parameters of what is presently defined as a tropical forest,” states geographer Jeff Chambers, affiliated with the University of California, Berkeley.
Predictive models derived from the empirical evidence amassed by Chambers and his collaborators suggest that these arid, high-temperature events will become notably more prevalent by the year 2100, persisting throughout the entire annual cycle, even during the conventionally wet season (typically from December through May).
A heightened rate of arboreal demise is anticipated, primarily due to reduced soil moisture. This deficiency can precipitate two interconnected challenges: hydraulic failure, where the ingress of air impedes water transport within the plant vascular system, and carbon starvation, a consequence of leaf stomata closing to conserve water, thereby compromising photosynthetic processes.
Empirical observations from the field confirm that these detrimental effects are already being observed amidst the extreme climatic conditions currently prevailing in the Amazon. Should the region transition to a hypertropical state, these extremes will occur with considerably greater frequency, potentially escalating tree mortality rates by 55 percent.
“Our findings indicated that trees characterized by rapid growth and low wood density exhibited greater susceptibility, succumbing in larger numbers compared to trees with high wood density,” notes Chambers.
“This observation suggests that secondary forests may face a heightened risk of drought-induced mortality, given their composition of a greater proportion of these particular tree types.”
A specific focus of the research involved two distinct Amazonian locations impacted by substantial droughts in 2015 and 2023. These events were demonstrably linked to unusually severe El Niño occurrences, which are driven by exceptionally warm oceanic conditions. The critical threshold for water availability remained consistent at both sites and across both years, pointing towards a potentially widespread ecological shift.
While the majority of hypertropical forests are projected to emerge within the Amazonian territories, the researchers anticipate similar phenomena may manifest in parts of Africa and Asia as well. These transformed forest ecosystems could transition from acting as carbon sinks to becoming net carbon emitters as tree populations decline.
These projections are grounded in comprehensive data analysis, serving as a stark reminder of the profound importance of forested regions to atmospheric equilibrium and the severe consequences of their degradation.
“The trajectory of these events is fundamentally contingent on our collective actions,” emphasizes Chambers. “The extent to which we actively orchestrate the emergence of this hypertropical climate rests entirely with us.”
“Should we continue to emit greenhouse gases without restraint, we will accelerate the advent of this hypertropical climate scenario.”
