What does science say about the climate crisis?
What do you think of when you think of the climate crisis? Close your eyes for five seconds.
What images do you see? Floods, droughts, scientists issuing warnings, ruined wheat fields, statistics with red lines, children and youths demonstrating, forest fires, a polar bear on a melting ice floe, newspaper cuttings, politicians debating? Or something completely different? What we associate with the climate crisis differs. It affects all parts of the world, all areas of life and society, and so ourselves too, in completely different ways. What they have in common is their trigger: the heating up of the Earth caused by humans. On this, science is unanimous.
The climate has repeatedly changed throughout the Earth’s history. The main driver in this is solar radiation: when it hits the Earth, some of it is reflected and some converted into heat radiation on the Earth’s surface. This heat radiation is stopped in part on its way back into space by gases in the Earth’s atmosphere; the greenhouse gases: for example, carbon dioxide (CO2), methane (CH4) or nitrous oxide (N2O). Without this natural greenhouse effect, which raises temperatures on the Earth’s surface to an average of 15 °C instead of -18 °C, the Earth would be frozen and life as we know it would not be possible. If changes occur in the amount of solar radiation reaching the Earth, or in the amount reflected back, or in the amount of converted heat radiation absorbed in the atmosphere, then the climate also changes. In the past, such shifts usually took place over long periods lasting thousands or hundreds of thousands of years.
What is new is that humankind is influencing the climate — and the warming is happening at a faster rate than ever before. Since industrialization, i.e. in just around 200 years, the average global temperature has already risen by 1.1 °C — in Austria almost twice as much at plus 2 °C. This warming is clearly caused by humans. The burning of fossil fuels such as oil, coal, and especially gas is pumping dangerous amounts of greenhouse gases into the atmosphere, especially CO2. But industrial processes, such as the production of cement, also cause CO2.
Greenhouse gases are also generated in agriculture, for example through the destruction of forests or moors, which releases stored CO2; through cattle farming, which causes methane; or through the fertilization of large areas of land, which produces nitrous oxide. All these processes are closely bound to the way we produce and consume: the more we produce, the more drastic the emission of greenhouse gas emissions. This further boosts the greenhouse effect and heats up the Earth. The result? A climate in crisis.
Sources:
IPCC – Climate Change 2023: Synthesis Report https://www.ipcc.ch/report/ar6/syr/downloads/report/IPCC_AR6_SYR_FullVolume.pdf
CCCA – Factsheet #35 2021 https://ccca.ac.at/fileadmin/00_DokumenteHauptmenue/02_Klimawissen/FactSheets/35_temperaturentwicklung_in_oesterreich_202110.pdf
What are consequences of the climate crisis?
Do a few degrees more really make a difference? Anyone who has ever left home without an umbrella knows how quickly the weather can turn. Just on those days when you don’t have a sweater in your rucksack, it can suddenly cool down by 6 °C. The climate is completely different. While the weather can change within a few hours, the climate describes the average state of the atmosphere in a certain area over a longer period of decades, centuries, or millennia. If the global average temperature drops by 6° C, for example, even a sweater won’t be enough — you’re in the middle of an ice age.
Small changes in the climate make a huge difference, therefore, with grave consequences. If global temperatures rise, that can have differing local effects: extreme heat, but equally so unexpected cold spells. Heavy rain becomes more frequent, but so do drought periods grow longer. The climate crisis already shows that clearly, in Austria, too: Weather extremes are on the increase. In summer, one hot day follows another, one tropical night after another. Forestry is increasingly plagued by bark beetles, while agriculture suffers from a chronic lack of rain and tourism from a lack of snow. When the rain does come, it is increasingly in dimensions that are catastrophic. We now experience one flood every eleven years; statistically, this should happen only once every 100 years.
The climate crisis is not some future scenario; we are right in the middle of it. But what we have felt in Austria so far is only a tiny part of it. Worldwide, extreme weather events are becoming both more frequent and more severe. Rising sea levels are already making some coastal regions uninhabitable. Those countries hardest hit by the climate crisis are in the Global South: here, extreme heat, droughts, and water shortages are destroying people’s habitats and livelihoods. More than three billion people around the globe live in areas severely threatened by the climate crisis.
Moreover, the effects of the climate crisis can be self-intensifying: If large areas of ice melt, for example, then less of the incoming solar radiation is reflected and the Earth’s surface heats up significantly more. This in turn melts more ice — a vicious circle. If critical thresholds are thereby reached, the climate system can change rapidly and drastically. Once such tipping points are exceeded, they can no longer be reversed. If Global Warming reaches over 1.5 °C, it becomes much more likely that we will exceed several tipping points.
If we continue as hitherto, then we are heading — even with the climate protection measures already agreed worldwide — for a rise in temperature of nearly 3 °C by the end of the 21st century. This would drastically exacerbate the consequences that we are already feeling. Thus, it is imperative to act quickly and effectively to contain the climate crisis and limit Global Warming.
Sources:
IPCC – Climate Change 2022: Impacts, Adaptation and Vulnerability. https://www.ipcc.ch/report/ar6/wg2/downloads/report/IPCC_AR6_WGII_FullReport.pdf
UNEP – Emissions Gap Report 2023 https://www.unep.org/resources/emissions-gap-report-2023; *Anm.: jährlich erscheinender Report – Aktualisierungen vorbehalten
What can stop the climate crisis?
In order to curb the climate crisis and its consequences, we must decelerate rising temperatures rapidly. There is much to do. In the Paris Climate Agreement, the global community committed itself to limiting Global Warming to 2 °C compared to pre-industrial levels — and to striving to prevent temperatures from rising above 1.5 °C. For half a degree already makes a huge difference.
To achieve this, global greenhouse gas emissions must be drastically reduced as speedily as possible: by around half by 2030 and to (net) zero by 2050. The Intergovernmental Panel on Climate Change (IPCC) provides the scientific basis for this and effective ways to achieve these goals in its regular reports. What needs to be done is therefore clear — but far too little is being done. With the measures taken so far, we shall probably exceed the 1.5 °C target before the end of this decade.
Countless solutions to reduce our emissions are already on the table. But where do we start? The best place is where particularly large quantities of greenhouse gases are pumped into the air. CO2 emissions are extremely uneven in their distribution. Historically, a few industrialized countries bear the main responsibility for the climate crisis — above all the USA and the European Union. So to make its contribution to reducing global greenhouse gas emissions, the European Union has committed to becoming climate-neutral by 2050. This can be achieved by replacing fossil-based oil, coal, and gas with renewable energies. In concrete terms, this means that wind and solar power in particular must be expanded quickly and across the board, and the necessary infrastructure, too. So that renewable energies can be used everywhere, too, many areas must switch to electrical energy — i.e., they must be electrified. This would entail our heating systems switching to heat pumps, and melting steel with electricity instead of coal. And since the most sustainable energy is still the energy that we do not use at all, overall energy consumption must be reduced at the same time.
Politics, business, all of us, are not impotent in the face of the climate crisis. On the one hand, highly specific measures exist for every area of the economy and life that can prevent the climate crisis from worsening in future. In mobility, for example, we need cars with electric instead of combustion engines, a strong focus on freight trains instead of trucks and planes, and an intensive expansion of public transport. In industry, we need to electrify, raise efficiency, firmly establish the circular economy, and build CO2 neutrality into processes. Buildings need to be renovated and insulated in order to reduce their energy consumption.
On the other hand, there are measures that mitigate the effects of the climate crisis. Here in Austria, these include desealing, soil protection, and renaturation, all of which contain the effects of future heavy rainfall. The National Energy and Climate Plan (NEKP) has outlined a possible roadmap for Austria to achieve the climate target set by the EU. Concrete political decisions are required to follow this path in reality.
