There is a widespread misconception that forests in industrialized countries of the northern hemisphere – Annex 1 countries under the United Nations Framework Convention on Climate Change (UNFCCC) – are not threatened, or are less threatened than tropical forests. This one report however, emphasizes that the opposite is true. Northern forests are facing massive losses of ecosystem integrity, biodiversity and carbon storage capacity that have been ongoing for decades.If this trend is not reversed, boreal forests could change from an overall net carbon sink to a carbon source as early as 2060.

What are boreal forests and why are they important? Northern forests are defined as the boreal and temperate forests of industrialized countries in the Northern Hemisphere, covering approximately 40 % of the global forest area and an equal share of the global forest carbon stock. Global forests are responsible for 91 % of total carbon sequestration in terrestrial ecosystems, with boreal forests contributing approximately 0.7 Gt of carbon annually (which is about 20 % of the global forest stock).

Key threats to boreal forests: The main causes of the decline in the carbon storage capacity of boreal forests and their degradation are:

• Climate-driven increase in natural disturbances: These include increased frequency and intensity of forest fires, pests (such as bark beetles), and drought. Boreal forest fires in 2021 caused record-high CO2 emissions. Since 2002, Canada has experienced increased tree mortality due to drought, resulting in biomass carbon losses of approximately 0.46 Gt per year.
• Unsustainable forestry: The prevailing model is clear-cutting rotational forestry, which degrades ecosystems, threatens biodiversity and is not suitable as a management model for climate change mitigation. In places like Sweden and Finland, rotational forestry has transformed 90% of forest area in the last 70 years, with 1,400 species in Sweden being severely affected by forestry.
• Loss of primary and old-growth forests: Less than 10% of northern forests are under any level of protection, a lower percentage than tropical forests, yet these old-growth forests are key carbon sinks and centers of biodiversity.
• Growing demand for wood: Consumption of industrial softwood (for paper and wood products) almost doubled between 1960 and 2010 and is expected to increase by another 75 % by 2050. This demand is the main driver of forestry intensification.

Declining carbon stocks and the risk of a tipping point: While the global net forest carbon stock increased between 1990 and 2020, the storage of northern forests decreased by 23 %. Canadian and Asian forests (especially in Russia) have transformed from carbon sinks to carbon sources. If this trend is not reversed, boreal forests could become total carbon sources by 2060, triggering the release of vast carbon stocks from biomass and soil into the atmosphere, leading to further warming in a self-reinforcing loop. Passing this critical tipping point would likely make it impossible to keep global warming below 1.5°C.

Unsustainable policies and misconceptions: Governments in northern forest countries rely on massive reforestation and afforestation measures (160 million hectares by mid-century) in their nationally determined commitments under the Paris Agreement (NDCs). However, the report argues that this is unlikely to be achieved without serious land-use conflicts and trade-offs for food security and biodiversity. Furthermore, it is often argued that intensification of forestry and increased logging can replace fossil fuels and materials, thereby achieving a positive climate effect. However, studies show that this “substitution factor” is between 0.4 and 0.8, meaning that the climate effect is negative. A wooden tree left to die and decompose in the forest is a more durable carbon store than if the same tree were harvested, processed and usedThe current carbon cost of global timber harvesting is approximately 0.8 Gt of carbon per year.

The Way Forward: Strengthening the Northern Forest Repository

To protect and restore the carbon stock of boreal forests, as well as their biodiversity and resilience, the following strategies are essential:

• Rapid reduction of greenhouse gas emissions in line with the long-term goal of the Paris Agreement.
• Effective protection of at least 30 % of all boreal forest ecosystems, including all remaining primary and old-growth forestsThese forests should be the first priority for protection.
• Halting the degradation of managed forests and restoring their resilience and carbon storage capacity. Expanding the volume of existing forests has the largest short-term positive effects on the carbon balance.
• Transition from rotational forestry and clear-cutting to forest ecosystem management (FEM). FEM is a promising solution that could increase the annual carbon storage in boreal forests by approximately 0.8 Gt (equivalent to 20 % of current global forest storage), while also addressing the biodiversity crisis and strengthening ecosystem resilience.
• Reducing unsustainable consumption of forest products, especially paper and wood.
• Limiting the use of bioenergy and stopping subsidies for burning trees and crops.

There is still room to change this trend, but urgent and decisive action is needed. Spring

Glossary of key terms

• Carbon Sink: Any process, activity, or mechanism that removes a greenhouse gas from the atmosphere. Forests are natural carbon sinks that absorb CO2 through photosynthesis.
• Carbon Source: Anything that releases carbon into the atmosphere, such as burning fossil fuels or deforestation. When a forest loses more carbon than it absorbs, it becomes a source.
• Carbon Pools/Stocks: Carbon pools stored in an ecosystem, such as living biomass (trees, plants), dead wood, soil and litter.
• Carbon fluxes: The movement of carbon between different reservoirs in an ecosystem.
• Annex 1 Countries: Industrialized countries, as defined in the United Nations Framework Convention on Climate Change (UNFCCC), that have committed to reducing greenhouse gas emissions.
• Boreal Forests: The largest terrestrial biome in the world, characterized by coniferous forests that grow in areas with long, cold winters and mild summers, usually between 50° and 70° north latitude.
• Temperate Forests: Forests growing in temperate climates, characterized by distinct seasons and often a mixture of deciduous and coniferous trees.
• Old-growth Forests: Forests that have reached advanced age without significant disturbance by humans or natural forces, characterized by complex structure, large trees, and accumulation of organic matter.
• Rotation Forestry: A forestry system in which trees are planted, grown, and harvested at regular intervals (rotation periods), often with the aim of maximizing timber production.
• Clear-cutting: A method of logging in which all trees in a given area are cut down, regardless of size or species.
• Deforestation: Conversion of forest land to non-forest uses (e.g. agriculture, development).
• Reforestation: Reforestation on land that was previously forested but has been cleared or degraded.
• Afforestation: The establishment of a forest or stand of trees on an area where there was no tree cover recently.
• Forest Degradation: Anthropogenic disturbances that lead to immediate or long-term loss or deterioration of the ecological integrity of a forest ecosystem.
• Tipping Element: A component of the Earth system that can respond in a nonlinear manner to climate change by transitioning to substantially different long-term states after key thresholds are exceeded.
• Kunming-Montreal Global Biodiversity Framework: An international agreement from 2022 that aims to halt and reverse biodiversity loss.
• Nationally Determined Contributions (NDCs): Climate commitments made by each country under the Paris Agreement.
• Integrated Assessment Models (IAMs): Computer models used to analyze the interrelationships between energy technologies, energy use, land-use changes, and societal trends that cause or prevent greenhouse gas emissions.
• Ecosystem-based Forestry: An approach to forest management that seeks to maintain healthy and resilient ecosystems by minimizing disturbance and mimicking natural processes, while taking into account multiple ecosystem functions.