Radiative Forcing of Arctic Carbon

Understanding how changes in carbon processes in the far north impact Earth’s energy balance

The Arctic-boreal region is undergoing more pronounced and rapid changes than any other area on Earth.

Wetlands are shifting, permafrost is thawing, wildfire frequency is increasing, and vegetation patterns are changing. These transformations impact many processes which regulate carbon cycling within the Earth’s systems.

Considerable effort and ingenuity have been dedicated to understanding the Arctic carbon cycle, yet substantial uncertainty remains regarding how the high latitudes will ultimately influence our changing climate. Many processes—such as changes in albedo (how much energy from the sun is reflected, instead of absorbed, by a material), plant carbon uptake, ecosystem greenhouse gas (GHG) emissions, and fire emissions—must be evaluated simultaneously. Some of these processes are likely to contribute to warming, while others may help mitigate it.

 

Our Work

Most previous studies have focused on determining greenhouse gas emissions in the Northern tundra-boreal region, without fully quantifying their impact on radiative forcing—a measure of the changes in the energy balance of Earth’s atmosphere. This project aims to take the next step by more deeply investigating the perturbation to Earth’s energy balance caused by terrestrial and aquatic greenhouse gas emissions, while also considering fire impacts and albedo.

a view of a sparse boreal forest from a tower. Two white beams stretch into the photo with scientific instruments mounted on the ends
a large creek with snowy banks

We are compiling a comprehensive, top-tier assessment of the recent trends in carbon dioxide (CO2) and methane (CH4) levels in the Arctic by leveraging a variety of best practices for estimating the carbon budget. This data will be compared against measurements of trace gas collected from tall towers and aircraft to diagnose regional sources of uncertainty in carbon fluxes.

a map of the northern region showing that while most areas are still carbon sinks, many areas in Alaska, Canada, and the northern regions of Russia are carbon sources

Models disagree about the magnitude of emissions from Northern Hemisphere tundra and boreal carbon ecosystems, whether they are a carbon sink or source, and how they are impacting Earth’s climate under current and future conditions. Through a multi-model analysis including bottom-up and top-down GHG estimate approaches, our study will identify areas of greater confidence and consensus in models, and apply the resulting multi-model ensemble to investigate how net GHG exchange from this region is influencing Earth’s climate.

We are also evaluating how changes in the carbon cycle and ecosystem properties (including albedo) are influencing global climate change by affecting the distribution of energy within the atmosphere.

Impact

This project will enable us to identify which ecosystems are currently contributing to climate warming (or in some cases, cooling) and shed light on how these systems might respond under future climate conditions. This is especially important to the many Indigenous and local communities for whom this region is home. The Arctic is particularly sensitive to climate change, and understanding its unique radiative forcing mechanisms helps clarify how local changes can influence global climate patterns.

This work targets several of the largest sources of uncertainty impacting climate projections. By reducing uncertainty in carbon (CO2, CH4) budgets, and enhancing our understanding of ecosystem feedbacks to climate, this work will provide valuable insights into the likely future evolution of our Earth system and ultimately supports more effective and targeted climate policies that can help mitigate global warming.

 

This research is funded through the NASA ABoVE project.

Partners & Collaborators

NASA Arctic Boreal Vulnerability Experiment (ABoVE) Carbon Dynamics Working Group The Permafrost Carbon Network