Scientists are adopting new research techniques to tackle the most visible impact of climate change — the so-called greening of Arctic regions.

A paper published today in the journal Nature Climate Change describes how the latest drone and satellite technology is helping an international team of researchers better understand how the vast, treeless region called the tundra is becoming greener.

The paper, led by two National Geographic Explorers from the University of Edinburgh and the University of California, Davis, also reveals that the causes of this greening process are more complex — and variable — than was previously thought.

Patterns within the pixels

As Arctic summer temperatures warm, plants are responding. Snow is melting earlier, and plants are coming into leaf sooner in spring. Tundra vegetation is spreading into new areas, and where plants were already growing, they are now growing taller. 

Understanding how data captured from the air compare with observations made on the ground will help build the clearest picture yet of how the northern regions of Europe, Asia and North America are changing as the temperature rises.

Researchers from Europe and North America are finding that the Arctic greening observed from space is caused by more than just the responses of tundra plants to warming on the ground. Satellites are also capturing other changes including differences in the timing of snowmelt and the wetness of landscapes.

“New technologies, including sensors on drones, planes and satellites, are enabling scientists to track emerging patterns of greening found within satellite pixels that cover the size of football fields,” said lead author Isla Myers-Smith of the University of Edinburgh’s School of GeoSciences.

Altering the carbon balance

Changes in vegetation alter the balance between the amount of carbon captured and its release into the atmosphere. Small variations could significantly impact efforts to keep warming below 1.5 degrees Celsius — a key target of the Paris Agreement. The study could help scientists determine which factors will speed up or slow down warming.

“Besides collecting new imagery, advances in how we process and analyze these data — even imagery that is decades old — are revolutionizing how we understand the past, present, and future of the Arctic,” said co-lead author Jeffrey Kerby, a postdoctoral scholar at the University of California, Davis, who was a Neukom Fellow at Dartmouth College while conducting the research.

Professor Scott Goetz of Northern Arizona University said the research is vital for our understanding of global climate change. Tundra plants act as a barrier between the warming atmosphere and huge stocks of carbon stored in frozen ground.

“We look forward to the impact that this work will have on our collective understanding of the Arctic for generations to come,” said Alex Moen, vice president of Explorer Programs at the National Geographic Society.

The paper’s authors include a team of 40 scientists from 36 institutions. It was funded in part by the National Geographic Society and government agencies in the United Kingdom, North America and Europe, including NASA’s Arctic Boreal Vulnerability Experiment (ABoVE) and the UK’s Natural Environment Research Council.

The research was also supported by the Synthesis Centre of the German Centre for Integrative Biodiversity Research, and was informed by a U.S. National Academy of Sciences workshop, “Understanding Northern Latitude Vegetation Greening and Browning.”

Additional authors from UC Davis include Professor Eric Post and Ph.D. student Christian John in the Department of Wildlife, Fish and Conservation Biology.