Abstract

The frequency and severity of droughts and heat waves are projected to increase under global warming. However, the differential impacts of climate extremes on the terrestrial biosphere and anthropogenic CO2 sink remain poorly understood. In this study, we analyse the effects of six hypothetical climate scenarios with differing drought-heat signatures, sampled from a long stationary climate model simulation, on vegetation distribution and land carbon dynamics, as modelled by a dynamic global vegetation model (LPX-Bern v1.4). The six forcing scenarios consist of a Control scenario representing a natural climate, a Noextremes scenario featuring few droughts and heatwaves, a Nocompound scenario which allows univariate hot or dry extremes but no co-occurring extremes, a Hot scenario with frequent heatwaves, a Dry scenario with frequent droughts, and a Hotdry scenario featuring frequent concurrent hot and dry extremes. We find that a climate with no extreme events increases tree coverage by up to 10 % compared to the Control and also increases ecosystem productivity as well as the terrestrial carbon pools. A climate with many heatwaves leads to an overall increase in tree coverage primarily in higher latitudes, while the ecosystem productivity remains similar to the Control. In the Dry and even more so in the Hotdry scenario, tree cover and ecosystem productivity are reduced by up to −4 % compared to the Control. Depending on the vegetation type, the effects from the Hotdry scenario are stronger than the effects from the Hot and Dry scenario combined, illustrating the importance of correctly simulating compound extremes for future impact assessment. Overall, our study illustrates how factorial model experiments can be employed to disentangle the effects from single and compound extremes.

Highlights

  • The terrestrial biosphere sequesters about 30% of the anthropogenic CO2 emissions (Friedlingstein et al, 2020)

  • We find that a climate with no extreme events increases tree coverage by up to 10 % compared to the Control and increases ecosystem productivity as well as the terrestrial carbon 10 pools

  • The decrease is strong for Temperate tree coverage in the Hotdry scenario (-5.6 %), while there is 140 little change in Boreal tree cover

Read more

Summary

Introduction

The terrestrial biosphere sequesters about 30% of the anthropogenic CO2 emissions (Friedlingstein et al, 2020). Different factors such as increasing atmospheric CO2 concentrations, higher temperatures, or, on a more regional scale, water or nutrient availability, can increase or decrease the terrestrial carbon sink. While warmer 20 temperatures are likely to increase productivity in high latitudes and altitudes due to an increase in the growing season length, productivity may be reduced in warmer regions because of higher evaporation and stomatal closure (Friend et al, 2014). Discussion started: 26 July 2021 c Author(s) 2021.

Objectives
Methods
Results
Discussion
Conclusion
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.