How plant heat stress will influence global warming this century
Role
Principal Investigator
Description
Our objective is to elucidate the mechanism, from subcellular to global scale, underlying the interdependence of plants and climate during Earth's current climate transition. This century, rising CO2 will force global temperatures to increase, pushing some vegetation systems into heat stress and potentially physiological collapse, irrespective of rainfall (1). Indeed, the most vulnerable regions are humid, high rainfall zones where 'wet-bulb' temperature (the lowest temperature that an evaporating object or organism can cool to) will rise to levels known to induce physiological stress and cellular death (2). Plants crucially affect climate through stomatal regulation of transpiration, which influences partitioning of net solar radiation into heating and evaporative cooling actions at the land surface (3). Plant vulnerability to heat stress can diminish this role and promote further climate warming, but little is known of the physiological and molecular mechanisms of stomatal regulation under heat stress, or of the combined physiological and climatic conditions that generate lethal leaf temperatures. This limits our capacity to predict and prepare for the long-term effects of global warming (4). This project will unlock mechanistic information from plant molecular genetics and heat stress physiology to formulate new theory describing stomatal regulation under temperature extremes, and apply this in an Earth system modeling framework to develop tools for predicting and adapting plant-atmosphere dynamics. Our central hypothesis is that previously unrealized breakdown of the stomatal regulation mechanism under heat stress, when expressed at the landscape scale, will add a significant and as yet unforeseen enhancing feedback to climate change this century. To test this, we will undertake the first coordinated integration and scaling of the stomatal control mechanism responding to heat under high CO2, from molecular signaling through to global fluxes, to quantify the full effects of plant heat stress on regional and global climate. Genetic and physiological methods will be used to develop and validate a new leaf-scale model of stomatal regulation at high temperature. This will be implemented in Earth system simulations to re-evaluate end of century climate scenarios in the most heatvulnerable regions using improved surface energy partitioning calculations.
Date
01 Mar 2024 - 30 Nov 2024
Project Type
GRANT
Keywords
photosynthesis;transpiration;carbon balance
Funding Body
Human Frontier Science Program
Amount
100000
Project Team
Alex Cheesman