Climate change 2/3: Changes we cannot escape

There is very little discussion in the public sphere about what awaits us in the future, or at least about what scientists believe awaits us in the context of climate change. Another key fact is the inertia of the climate system. Even if humanity miraculously stopped emitting all greenhouse gases overnight, warming would not stop immediately, which must be emphasised [1].

The climate system (especially the oceans) responds with a delay to already elevated CO₂ concentrations. NASA states that if we stopped all emissions today, temperatures would stop rising within a few years, but would remain elevated – and the climate would remain shifted to a higher level for centuries. In other words, global warming is already under way and cannot be reversed all at once. Some changes (such as glacier retreat, ocean warming or rising sea levels) are essentially irreversible over timescales of hundreds to thousands of years. [2].The IPCC states with high confidence that global temperatures will continue to rise for at least the next several decades (primarily depending on emissions to date). This means that even with aggressive emissions cuts by 2030 or 2040, we will not avoid certain significant impacts – we must adapt to them[3].

What the world will look like specifically at warming of +1.5 °C, +2 °C or more cannot be said with complete certainty, but scientific projections offer a rough idea. NASA mentions, for example, more frequent and severe wildfires, longer periods of drought in some regions and, conversely, more intense torrential rainfall and hurricanes elsewhere[4]. Already today, weather extremes are breaking records – heatwaves, devastating floods, persistent droughts and megafires are becoming the new reality. Many areas – especially in the tropics and subtropics – could become almost uninhabitable due to a combination of heat and humidity that exceeds the physical limits of human thermoregulation[5]. Projections suggest that living conditions on Earth will change significantly by the end of the century; beyond weather, this also includes the loss of fertile land, declining agricultural yields, the extinction of ecosystems and the spread of tropical diseases into new areas.

One of the most serious social consequences could be so-called climate migration. If certain countries or regions are hit by extreme droughts, crop failures, water shortages or rising seas (directly threatening the existence of coastal communities and islands), a mass exodus of people from affected places can be expected. Even today, we can observe that extreme events lead to population displacement – for example, the prolonged drought in Syria preceded the conflict and migration there, while cyclones are forcing thousands of families from island states in the Indian and Pacific Oceans, and so on. As early as 1990, the IPCC warned that the greatest impact of climate change could be population movements involving millions of people[6]. More recent estimates even speak of tens to hundreds of millions of potential “climate refugees” in the coming decades (although precise figures are highly uncertain and depend on how quickly we cut emissions and how the world cooperates on humanitarian assistance).

What is certain, however, is that conditions on the planet will change fundamentally by the end of the century, along with the conditions for human life. Under a relatively optimistic scenario of warming of around 1.5–2 °C, we will face new challenges in food and water security, coastal protection, managing extremes and population resettlement.

We therefore face a dilemma: Does it make sense to make enormous efforts to cut emissions when we will not be able to reverse certain changes anyway? Should we not instead focus our resources on adapting to the changed climate, or even try to actively reverse the trend using new technologies?

Adaptation vs. mitigation: where should efforts be directed?

Experts’ answer to the above dilemma is generally that we cannot give up either mitigation (emissions reductions) or adaptation – we need both simultaneously [7]. The reason is that we have already been dealt the cards of a certain degree of warming to which we must adapt, while we can still influence how much the climate changes in the future. NASA describes it by saying that we are already committed to a certain level of warming, but how many degrees it will ultimately be depends on our future emissions [8]. Adaptation without mitigation would lead to a dead end: if we did not curb emissions, warming would exceed 3 °C, 4 °C or more, which would likely mean catastrophic impacts to which it would be impossible to fully adapt. Mitigation without adaptation, meanwhile, would ignore the reality that changes are already under way – even at 1.5 °C of warming, it will be necessary to invest in flood protection, building infrastructure resilient to extremes, changing agricultural crops and so on.

However, some experts point out that the debate is unbalanced: most political energy (and funding) is directed towards cutting emissions, while adaptation is overlooked or underestimated. Yet both rich and poor countries will have to adapt – and for poorer countries this will be especially difficult without assistance. We can already see adaptation in practice: flood barriers are being built, more resilient crops are being tested in agriculture, cities are introducing so-called green infrastructure (parks, street cooling) to counter urban heat islands, while in the Czech Republic this includes greater efforts to retain water in the landscape, and so on. Nevertheless, there is talk of an “adaptation gap” – the gap between adaptation measures that are needed and those actually financed. Going forward, it may make sense to invest more in society’s resilience, because we will not stop a certain degree of change. For example, in the budgets of the EU and its member states, adaptation projects (water retention in the landscape, reforestation, climate-resilient buildings) should have similar priority to clean energy projects [9].

A third pillar of the response to the climate crisis is also beginning to be discussed: geoengineering. This is a set of ideas for technically intervening in the planet’s climate and artificially reducing temperatures, for example by spraying aerosols into the stratosphere to reflect some solar radiation (simulating a “volcanic winter”), or conversely by artificially removing CO₂ from the atmosphere on a large scale and storing it underground. These concepts were taboo for a long time, but as concern grows that warming cannot be kept within 1.5 °C, they are moving to the forefront of scientific research. Some climate scientists argue that geoengineering could be a useful “Plan B” should mitigation fail to prevent dangerous warming [10].

For example, solar geoengineering (reflecting solar radiation with aerosols) could theoretically reduce global temperatures quickly – the question is at what cost and with what side effects. Critics warn that such interventions may have unforeseen consequences for regional climate (such as changes to monsoons or the ozone layer) and that they do not address the cause (greenhouse gases), merely temporarily mask the effect. There are also ethical and geopolitical questions: who would decide on such a global intervention, and could one country unilaterally “set the Earth’s thermostat”? [11].

Nevertheless, research in this field is advancing. For now, the prevailing view is that geoengineering is not a substitute for emissions reductions, but could become a supplementary emergency measure. The condition, however, would be securing public support, which is currently highly uncertain; scientists therefore stress the need to communicate openly about potential risks and benefits so that the public and policymakers understand the entire issue. For now, any real-world application of these methods remains more a matter for the future and an extreme scenario [12].