In political discourse, the green transition has turned into a bludgeon. That's somewhat unfortunate, because the root cause has not changed in the slightest. Earth's system is rapidly shifting away from the relatively stable post-glacial state it has maintained for the past 11,700 years — the Holocene. This is the epoch that gave rise to civilizations and, as far as we know, is the only one in which human society has ever existed.

Over the past half-century, global warming has entered a new trajectory: 0.2°C per decade. The average temperature over land — which warms faster — has risen by 1.6°C during that time. The likely main culprit is human-generated greenhouse gas emissions such as carbon dioxide, methane and nitrous oxide. Eighty percent of these emissions stem from energy, industry, transport and construction, while 20 percent come from land use changes such as agriculture and forestry.

Societies are striving to decarbonize their economies and reduce carbon emissions across all areas of life, particularly in energy production. Apart from temporary dips during major economic crises — including the one caused by the COVID-19 pandemic in 2020 — fossil fuel carbon dioxide emissions have steadily increased, growing at an average annual rate of 1 percent over the past decade.

Today, anthropogenic CO2 emissions amount to roughly 40 billion tons per year. About 29 percent of this is absorbed by terrestrial ecosystems (mainly forests, through a process known as CO2 fertilization, where higher atmospheric CO2 levels accelerate plant growth) and 26 percent is absorbed by the oceans (through dissolution in seawater). The remaining 48 percent accumulates in the atmosphere, causing atmospheric CO2 concentrations to rise by approximately 2.5 parts per million (ppm) annually. So far, the proportion of CO2 absorbed by land and ocean systems has remained stable, but whether that will continue is uncertain.

Thanks to the ocean's vast volume, circulation patterns and high heat capacity, it has absorbed more than 90 percent of the excess heat retained by Earth. By comparison, land and the atmosphere have absorbed less than 5 percent of this excess heat, with the remainder going into melting continental and sea ice.

It is precisely because of the ocean's heat capacity that we haven't already cooked. But that comes at a cost: thermal expansion of ocean water and rising sea levels. At present, the average global sea level is rising by just under half a centimeter per year. This global rise is more likely to accelerate than to slow down and already surpasses the rate of land uplift along Estonia's coastline. That's bad news for Estonia's coastal cities, where storm surges are increasing the risk of flooding, and for the low-lying areas of Western Estonia, where saltwater intrusion is transforming habitats.

Climate inertia and domino effect

A rapid and drastic reduction in greenhouse gas emissions would slow the pace of global warming in the coming decades, but it would not bring it to a halt or reverse it. The high-inertia climate pendulum, set in motion by the atmospheric overdose of greenhouse gases, has taken on a life of its own and is triggering a domino effect across other components of Earth's biosphere.

The summer retreat of Arctic sea ice reduces Earth's albedo — that is, its reflectivity. Sunlight that would otherwise be reflected back into space is instead absorbed by the ocean and dispersed as heat. A similar effect comes from the melting of continental glaciers, which exposes dark ground surfaces. Considering global warming as a whole, the albedo change from the Arctic alone is equivalent to about one-quarter of the impact of carbon dioxide emissions.

Secondly, thawing permafrost is like a climate time bomb with a short fuse. We don't know how much methane might be released into the atmosphere as a result. Sea level rise caused by warming will continue for several centuries until a new equilibrium is reached. That presents a bleak outlook for coastal areas, where a significant share of the global population, infrastructure and economy is concentrated.

Whining will not stabilize the climate

Each additional degree of warming escalates extreme weather events and associated damage, including loss of biodiversity. One would like to hope that the global boom in wind and solar energy will rein in fossil CO2 emissions in the coming years, but a return to the pre-industrial Holocene safety zone may remain an illusory dream for centuries.

Our planet is burning right now. Its most tangible impact is the increasing frequency and intensity of extreme weather events — heatwaves, droughts, storms and torrential rains. As already mentioned, rising sea levels combined with stronger storms lead to flooding, displacement of human populations and changes in ecosystems.

However, risks can be turned into opportunities. Broadly speaking, we have two main courses of action. The first is to wean ourselves off our dependence on fossil carbon as quickly as possible. The second is to begin adapting land use now to match the climate conditions likely to prevail 50 years or more from today.

We should start considering which approaches to land management and conservation will be suitable for our region in the future. A bold step would be to prepare for the return of an Atlantic climate period, which once prevailed in the Baltic Sea eco-region nearly 5,000 years ago. The cornerstones of a climate-resilient society in terms of land use are agroecosystems that support food security under new conditions and forest ecosystems that preserve biodiversity, provide renewable bioresources and offer climate mitigation.

What are our choices?

Food security may well be a human right, but it is not a law of nature. Just a couple of human generations is enough for us to grow accustomed to food coming from store shelves. It's easy to get used to good things — the reverse is the real challenge.

The plant and animal varieties that have fed us for decades or even centuries may no longer be optimal in tomorrow's climate. Today's finely tuned agroecological methods may soon lose their effectiveness. Changes in soil properties and soil life are difficult to predict. We're facing conditions that will require new, more climate-resilient crops and entirely new farming techniques.

Agriculture isn't the only sector facing these challenges — similar trials await other forms of land use such as forestry, semi-natural habitats, wetlands and water bodies. Across all land use types, we need to account for global trends like the decline in biodiversity and the homogenization of ecosystems, meaning a loss of regional ecological uniqueness.

Human society's ability to adapt to rapid change will be a fascinating test. Climate-driven land use changes don't have to be catastrophic or apocalyptic. We can turn them into opportunities and advantages — if we prepare for them carefully. Delaying adaptation will only drive up costs and jeopardize both feasibility and effectiveness. The biggest roadblocks are in our own minds — chiefly, our "maybe-this-cup-will-pass-from-me" mindset. Clearly, it won't.

In this accelerating phase of change, uncertainty about the climate resilience of traditional land use methods is growing. While there's more uncertainty than we'd like, the decisions we make now will shape land use for the next century. So far, we've done well on food security. But in an era of climate turbulence, it's no longer guaranteed. The threats — intensifying heatwaves, prolonged droughts and episodes of torrential rain — are real and growing.

Developing and involvement of domestic research competencies

Changes in biodiversity, the arrival of new pathogens, new species and new crops — we lack the knowledge and experience to deal with them. That knowledge must be developed now through broad, cross-disciplinary scientific research. Delays and dealing only with the consequences later will raise the risk of social and economic catastrophe to intolerable levels.

Our task is to adapt agroecosystems to rising temperatures, increasingly erratic precipitation patterns and the global CO2 fertilization effect already mentioned. We must preserve and enhance soil biodiversity, carbon content, moisture retention capacity and erosion resistance. The climate resilience of the soil-plant system must improve. At the same time, we need to prepare for the introduction of new crop species better suited to tomorrow's climate.

In both agriculture and forestry, we must prepare for the arrival of new pests, plant diseases and pollinators — due both to climate-driven shifts in range and to international trade. All of this will affect the biodiversity and functioning of agricultural landscapes, grasslands and both commercial and protected forests.

Several native tree species — for example, the Norway spruce — are becoming increasingly vulnerable to intensifying heat and drought. Weakened trees are easy targets for pests, which can trigger a domino effect that devastates forests, undermines carbon sequestration and causes economic damage.

Forest adaptation to climate change may mean the replacement of boreal species with broadleaf ones, as was the case during the Atlantic climatic period. These new realities can be turned into opportunities through well-informed adjustments to forest management practices. Trees shape the forest habitat. When tree species change, it cascades through the entire forest ecosystem — from soil microbes and fungi to meiofauna and epiflora, insects and vertebrates.

Heatwaves increase the risk of wildfires and damage mitigation is becoming more expensive. Storm damage is also likely to intensify. To reduce these risks, forestry practices must be adapted accordingly.

Warming intensifies evaporation and a warmer atmosphere can hold more moisture. While total precipitation is expected to increase, we must prepare for more uneven distribution over time and space. The risk of intense downpours and flooding will grow in both urban and rural areas, and we must be ready. Sudden heavy rains cause erosion, carrying nutrients from fields into water bodies and accelerating eutrophication.

Eutrophication — excessive nutrient enrichment of water bodies — is intensifying in inland waters and coastal seas. Combined with stronger thermal stratification, oxygen levels in deeper layers of water bodies are dropping, harming living conditions and reducing biodiversity. Keeping water bodies in good ecological condition will require even greater effort from society. As waters warm, this will impact fish populations and fisheries. Cold-water species will struggle (such as vendace, salmonids, whitefish, smelt), while warm-water species will thrive (such as pike-perch and catfish).

Wetlands, whether natural or managed, capture and store carbon because decomposition of organic matter is inhibited by water saturation. For the same reason, wetlands also emit potent greenhouse gases — methane and nitrous oxide. The net effect on greenhouse gases and biodiversity must be carefully considered using the best available knowledge when planning costly land improvement projects or forest-to-wetland restoration efforts.

Projections for global sea level rise have consistently underestimated actual measurements. By the end of the century — which is not far off — the average of current models forecasts a rise of nearly 90 centimeters. Although proactive planning in coastal areas can help mitigate the impact, the coming centuries will demand large-scale infrastructure relocation and the resettlement of people to safer areas.

Habitats are changing — not only for animals and plants but for people as well. On one hand, we face heatwaves and droughts that directly and indirectly affect us through forced land use changes; on the other, there's the encroaching ocean along the coasts. It's likely that the defining issue for societies in the next century will be managing mass climate migration, affecting hundreds of millions of people. Political leaders whose constituencies are not particularly refugee-friendly should be especially outspoken advocates for climate mitigation measures.

Alleviation in the choices we can make

The decarbonization of energy production must be a top priority — particularly with regard to fossil carbon. Covering peak energy demand with biomass is not a popular idea. But biomass cycles and renews over the course of roughly a hundred years, whereas fossil carbon takes a hundred million. Too often, we don't have the luxury of making good choices — only the option to choose between the bad and the worse.

Fossil-based materials should be wisely replaced with bio-based alternatives — that is, rapidly renewable resources. This presents an opportunity for forestry and agriculture. Wherever possible, fossil carbon should stay underground. Land use adaptation already allows us to increase carbon capture and storage today. That's an opportunity we would be foolish to pass up.

One key lesson from evolution and ecology is that diversity is the best insurance policy against a changing environment. For that reason, it's wise to maintain diversity in land use and biodiversity. Nature adapts to a changing climate through changes in living organisms. As the planet warms, species migrate toward cooler latitudes. Devoting a large portion of society's resources to fighting incoming non-native species is a losing battle if the root cause remains unaddressed.

When we speak loudly about nature conservation or environmental protection, we're at least partially hiding behind a euphemism. For the most part, we're really trying to protect ourselves — more precisely, our accustomed societal structure and the comfort zone of the Holocene. To creatively paraphrase a famous line from the cult film Jurassic Park, "life finds a way": nature will take care of itself. But will our societal system survive? And if it does — at what cost?

Synergy and conflict

Climate change mitigation efforts often support the achievement of other sustainable development goals, but conflicts can also arise that require compromise. Stimulating biological carbon sequestration — such as afforestation, the development of sustainable forestry practices and increasing soil carbon content — promotes biodiversity recovery, ecosystem services and community well-being.

However, the goals of conserving biodiversity and mitigating climate change do not always align. For example, afforestation — planting forests in areas where none previously existed — does enhance carbon capture but can be harmful to local biodiversity. Similarly, removing dams from rivers and streams restores fish migration routes but may reduce the extent of wetlands and the diversity of habitats.

Wetlands store and retain carbon, but they may also release methane. They provide critical habitat for endangered amphibians, help mitigate flood risk, extend water retention time in landscapes and thereby reduce eutrophication in downstream water bodies and coastal seas. Draining waterlogged soils can boost forest growth and carbon sequestration.

This complex web of trade-offs involves many moving parts. The best policymaking requires in-depth scientific research, optimization across multiple goals and the minimization of conflicts.

Promoting climate literacy is foundational to building public readiness. Implementing mitigation and adaptation policies depends on public awareness of climate impacts and risks. Both citizens and the private sector must be engaged. It is wise to harness market forces in finding solutions — they may prove more effective than relying solely on regulatory measures.

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