The amount of black carbon, predicting threshold values and the intricate mosaic of the Arctic landscape are key issues when studying the Arctic climate

Professor Atte Korhola is studying how changes in the Arctic environment relate to climate change. He describes three particularly topical research issues.

1. Predicting threshold values helps us prepare

Rapid, major environmental changes are happening in Arctic areas – but we lack the methods to interpret them. Have we already exceeded the thresholds after which the changes will be difficult to stop, or is the environment so flexible to changes that it is possible for it to recover?

 “It is important to identify the warning signs that suggest we’re approaching threshold values so that we can prepare for major environmental changes in time,” says Atte Korhola.

Korhola is professor of environmental change at the University of Helsinki, and a member of several international research networks focusing on climate conditions and the climate responses of various ecosystems.

He provides one example of what it may mean when a threshold value is exceeded:

 “We know that changes in the environment advance climate change – and vice versa. One such feedback loop is the decrease of the ice and snow cover on the Arctic Ocean. The shrinking of the ice advances the warming of the climate, which in turn reduces the amount of ice and snow. Under normal conditions, snow reflects most of the sun’s rays back into space, but as the area with no snow cover increases, the sun’s radiation will be increasingly absorbed by the sea and land, which will make them warmer.

Some researchers believe that the changes taking place in the Arctic Ocean is already irreversible and that we are in an ever-deepening vicious cycle.

A similar self-perpetuating process can be seen in the melting of the permafrost in the Arctic region. The melting releases methane from the ground into the atmosphere. This warms the climate, which will then further accelerate the melting process.

 “But the point at which the situation spirals entirely out of control, and whether such a tipping point even exists, is a major challenge for scientific research,” states Korhola.

 “For us to be able to interpret the warning signals early and to make prognoses, we need more research into the flexibility and resilience of ecosystems. To recognise the threshold points we require statistical mathematics and long time series,” says Korhola.

 “There is little monitoring data from Arctic areas, but luckily we have excellent indirect paleoclimatological data, stored in peat deposits, lake sediments and glaciers in the area. These will help us gain an understanding of the dynamics of ecosystems, enabling us to draft forecasts for the future.”  

Korhola’s group is currently studying how long northern peatlands can remain carbon sinks, and at what point they will turn into sources of carbon as global warming progresses. The researchers are measuring the amount of carbon in the peatlands, monitoring plant cover and creating a variety of different models to identify warning signals about changes to the peatlands' climate response.

2. The Arctic mosaic – small details influencing the whole

According to the definition of the Arctic Council, the Arctic region encompasses areas belonging to eight different countries, and its area is approximately 14.5 million square meters, of which two-thirds consists of water surrounded by land mass. Despite the challenging conditions, humans have been living in the region for millennia.

The Arctic region is not a single monolith or a homogenous environment. It is a mosaic of small lakes, ponds, periglacial landforms, blockfields, peatlands and wetlands, a uniquely varied environment in the world.

Korhola’s research group wants to understand how small details influence the whole: how carbon flows through the Arctic landscape, where is it stored and where released.

 “We are studying the Arctic region like a mosaic, piece by piece,” Korhola explains.

According to Korhola, only about one third of the predicted warming of the climate is directly caused by carbon dioxide, or the acceleration of the greenhouse effect. Everything else results from ecosystem responses, their reactions to a warmer environment. Will they become carbon sinks or carbon sources – will they absorb carbon dioxide from the atmosphere or release greenhouse gases that accelerate global warming?

3. We must cut down the amount of black carbon

Generated as a by-product of incomplete combustion, black carbon, or soot, is a significant human cause contributing to global warming. Black carbon is carried along air currents to the Arctic, darkening the surface of snow as it descends and accelerating the melting of the snow and ice. This is a serious threat which has also been raised in the discussions between Presidents Niinistö and Trump earlier this year.

In the Arctic region, black carbon is the second most significant anthropogenic factor in global climate warming after carbon dioxide, with some researchers claiming it is the most significant.

Researcher Meri Ruppel from Korhola’s research group has been conducting measurements of sheet ice core sample series, which indicate that the amount of black carbon appears to be on the rise in Eurasia.

 “Our hypothesis is that the source of the increase in black carbon is primarily the extensive flaring emissions on Russia’s oil and gas fields. The flares can even be seen from space,” Korhola explains.

In waste flaring, gas which cannot be stored in the pipes is burned. According to Korhola, such flaring should be banned immediately, as it spreads soot in the delicate Arctic area and accelerates climate change. Putting an end to flaring would have an immediate positive effect on the climate.

Links:
Environmental Change Research Unit ECRU

Arctic Monitoring and Assessment Programme AMAP, an Arctic Council working group