A 2013 paper from researchers across Europe, published in Nature Climate Change, suggested that European forests were nearing saturation with regard to absorbing carbon. The paper, which was entitled ‘First signs of carbon sink saturation in European carbon biomass’, concluded that policies would need to be modified if European forests were to continue to act as net absorbers of carbon in the future. The authors realised that the exact policies needed to increase carbon sequestration will differ depending on local conditions. They did, however, make a number of suggestions:

• Conserve old forests not at risk of disturbance.
  
  
• Harvest unproductive, old forests that are at high risk of disturbance. This will lead to some increase in carbon emissions, but is better than harvesting the undisturbed forests.
  
  
• Conserve forests on sensitive sites, steep slopes and in areas of high-carbon soils.
  
  
• Increase protective measures for forests at particular risk of fire.
  
  
• Where possible, switch to continuous cover forestry techniques, rather than cutting down whole areas of woodland (clear-felling).
  
  
• Improve overall management where wood is grown for timber.
  
  
• Aim for short growing cycles where wood is grown for use as a bio-energy fuel.
  
  
• Plant more forests, while conserving existing ones.

Although in recent decades European forests have removed carbon from the atmosphere, the picture over a longer timeframe is far from clear cut. A recent paper from CNRS researchers in France, examining European forests from 1750 to 2010 CE, suggested that changing forestry practices had actually led to an increase in carbon dioxide emissions, despite an overall increase in forest area. The researchers attribute this to a trend to the replacement of broadleaf trees by more economic conifers. Although these conclusions can be disputed, they do show that simply ‘planting trees’ may not have a beneficial effect on carbon dioxide emissions. As is often the case, the devil is in the detail. Careful evaluation of tree planting programmes is needed in order to make sure that their overall effect is to remove carbon dioxide from the atmosphere. Yes, boreal forests can definitely act as a carbon sink and they are undoubtedly one of our most effective tools in fighting climate change, but we need a carefully coordinated approach with a higher level of cooperation across many borders to make sure that carbon sequestration is exactly the direction we're headed in.

Forest fires are an environmental challenge that must be minimised, in order to prevent unnecessary carbon dioxide emissions. As fires do not always politely stop at political borders, transnational coordination is required to minimize their effect. It is not clear whether the overall effect of a warming climate will be to increase or decrease forest fires. Forest fires are favoured by dry weather, but may be ignited by lightning strikes. Researchers from the Institute for Environment and Sustainability (a Joint Research Centre of the EU) in Italy examined forest fires in Russia. They concluded, in a 2007 paper, that the majority of fires were caused by human actions rather than lightning.

The fauna of the boreal forests are a significant part of the whole ecosystem. Large animals, such as European elk (known as moose in North America), reindeer, brown bears and grey wolves, need to move freely over large areas in order to sustain healthy populations. Infrastructure, such as roads, railways and border fences, needs to be planned so as not to have too detrimental an effect on their free movement. This is another area where international cooperation is important. As the earth warms in the future, various changes to forests can be expected to occur. As Arctic areas warm, the boreal forest may push further north, gradually taking over more of the Arctic tundra. At lower latitudes, we may see an increase in broadleaf trees at the expense of conifers in the southern portions of the boreal forests, as the former are usually favoured by higher temperatures.

Research on boreal forests was summarised by a 2007 review article by Canadian researchers, entitled ‘Introduction. The Boreal Forest and Global Change’, which introduced a themed issue of the journal Philosophical Transactions B. Several important topics emerge from this summary. Firstly, the authors note that the ecology of the boreal forests is poorly understood compared to that of many other ecosystems. More research is needed. The future response of the forest to climate change is uncertain. It is clear that the treeline (i.e. where the boreal forest gives way to the open tundra) was further to the north 7,000 to 10,000 years ago, during the warm period known as the ‘Holocene Thermal Maximum’. Although northern movement of the treeline is expected in the future, it will probably be very slow, as the treeline has still not fully recovered from a retreat during the ‘little ice age’ (1500 to 1800 CE). There are many uncertainties regarding the extent of any recolonization and which species of trees would benefit most. The study also notes that northern forests in Eurasia are largely managed by humans, rather than being totally natural vegetation. This is particularly the case in Scandinavia, where intensive management for timber and other wood products is the norm. Thus any future forecasts for the forest must take into account economic and social factors, rather than simply assume a return to the state of affairs that prevailed in distant warm periods, where the effect of the human population was much less.

Another complicated topic that effects carbon emissions is the production of methane in northern lakes, bogs and fens. Methane is an important greenhouse gas, so any significant increase in its rate of production from natural sources needs to be prevented. Variables such as water levels and average temperatures can affect how much methane is produced. A related topic is the future melting of permafrost. This permanently frozen ground occurs largely in tundra regions, but can also be found to some extent in boreal forest areas. It is feared that melting of the permafrost may release large quantities of methane, which will then cause more global warming; this is a particularly nasty example of positive feedback. A 2015 summary of the effects of losing permafrost on global warming was produced by experts at the Wood Hole Research Center in the US.

It can be seen that any European response to climate change must involve consideration of forestry policy. No credible coordinated response is possible without the participation of Russia, as it contains the bulk of Europe’s boreal forest. This is not only a vitally important ecosystem for the management of climate change, but it is also Europe’s most important collective weapon in the fight against it. International cooperation has worked well in the past; for example, international collective action from countries with widely different political systems helped protect the ozone layer by phasing out the chlorofluorocarbon chemicals that were damaging it. The European Space Agency and Roscosmos (the Russian Space Agency) have also enjoyed a long-standing partnership in the exploration of outer space and have recently teamed up for a series of missions aimed at searching for life on Mars.

The fact that the rest of the world looks to Europe for clear leadership on environmental protection and adopts the standards that are set here brooks no argument. It is now essential that the different blocks in Europe, most notably the EU and the EAEU, set aside their differences and cooperate irrespective of political ideologies, boundaries or any other man-made line in the sand. We are now faced with a historic opportunity to come together as nations, scientists, engineers, indeed people from all walks of life and forge a collective culture of sustainability that extends beyond our current conceptualisation of boundaries, whilst inspiring others around the world to rethink theirs too. Habitat loss and pollution are indifferent to borders and the science is absolutely clear: time is running out and if we truly are serious about saving this planet; we have no other option than to unite forces and focus on the immediate next steps that need to be taken.