NOW

the most pressing issue of our time:

the climate crisis

Since 2020, the Corona pandemic has kept the whole world holding its breath. In the blink of an eye a novel virus had turned all of our lives upside down. Since February 2022, a senseless war of aggression, instigated by Russia against Ukraine, has caused unimaginable suffering there but has also aggravated pre-existing global problems.

A far more wide-ranging crisis has thus (once again) receded into the background of worldwide attention—albeit its consequences will be significantly more far-reaching—not only for human but for all life on Earth: the climate crisis. This existential threat we face today is only the most marked symptom of a novel global imbalance: Since the beginning of the industrial era not only has humanity grown explosively, it has also immensely intensified its impact on its natural living environment. As of now, the biggest planetary-scale changes do not originate in nature anymore but are initiated by man. So, welcome to the Anthropocene [1], a new geological epoch, in which mankind has become the domineering force on the planet . . .

During the last 200 years mankind has caused unprecedented global heating. One of the many consequences: 19 of the 20 hottest years on record have occurred between 2001 and 2020.[2] On a more extended timescale, global mean surface temperature (GMST, land and ocean) has been raised by 1.2 °Celsius (C) since the beginning of the industrial era.[3]
1.2 °C may not sound like much, but we are considering average global temperature here: that is the median of all concretely measured temperatures around the globe over a period of at least 30 years. In many places temperature rises have been much higher—5-6 °C in the Arctic, for example. Seen from the perspective of global mean temperature a rise of 1.2 °C is immense: with that it is now warmer on Earth than it has been during the last 120,000 years [4]—since before the last ice age during which GMST was only a few degrees Celsius lower. Every degree of mean temperature rise or drop counts very clearly, the more so the stronger the deflection in one direction. A world heated by another 3 °C—a so-called »hothouse Earth«—would have equally devastating consequences for both environment and civilization as would another ice age.[5] 
From today’s perspective it is obvious that human civilization could only emerge during the last 12,000 years—the climatically exceptionally stable interglacial period of the Holocene: Humans became sedentary, adopted agriculture, developed advanced civilizations and technologies—and as a consequence of all these advances ended the very geological epoch, which had made them possible in the first place.

there is no doubt about the

causes of the
climate crisis

Today there is unequivocal evidence that global heating and the climate crisis have been caused almost exclusively by human activity during the past 200 years: Rising concentrations of greenhouse gases in Earth’s atmosphere—most prominently of carbon dioxide (CO2)—have been caused mainly (two thirds) by the combustion of fossil fuels coal, oil, and natural gas (this combusted carbon exhibits specific carbon isotope signatures, which attest to its source [6]). Another third of increased greenhouse gas levels stems mainly from »land-use change« (see next section).
Mankind owes a lot to the cheap fossil energy sources which were rendered accessible during the industrial era: 1. An enormous 90-fold (!) expansion of human economy between 1820 and 2015. – 2. An exploding world population, which has tripled to 7.8 billions today within just a single lifetime. – 3. A level of global energy consumption which has grown exponentially since the 1950s (see graphic). We heat with fossil fuels, we combust them inside almost all our means of transport, they fuel a large part of industrial production, and they are used to generate roughly two thirds of worldwide power/electricity: Coal, oil, and gas still cover 86% of global primary energy demand.[7]

Besides the carbon emitted to the atmosphere by the burning of fossil fuels industrial agriculture and related land-use change (LUC) are the second-most important driver of rising greenhouse gas levels. Enormous areas of virgin (rain)forest—predominantly in the Amazon region, on Borneo and Sumatra, and in the Congo basin—have been lost to expanding agricultural lands during the past decades. These newly deforested lands (most often cleared by slash-and-burn methods) are used mainly for feed production for livestock from all over the world (mainly soy and wheat), as grazing lands for livestock, and for oil palm plantations (palm oil is the cheapest and poorest plant oil used in many industrial foods). The carbon which had previously been stored in these trees/forests was thus emitted to the atmosphere again. In addition, nature’s capacity to act as a carbon sink (by sequestering carbon from the atmosphere in plant tissue) is thus decimated. By clearing so many forested areas industrial agriculture has also become the main driving factor in today’s accelerating biodiversity loss (see under »impacts«).
But livestock production contributes to global heating in yet another way: as a byproduct of their digestive process ruminants like cows release methane (CH4), a greenhouse gas 28 times more potent than CO2. Who believes all these to be marginal problems should consider these statistics: 97% of all land animal body mass on Earth today are made up of humans (30%) and the livestock they raise (67%).[8] 77% of worldwide agricultural lands are dedicated solely to feed production and the raising of livestock.[9] Yet, in caloric value terms meat and dairy products only contribute 18% to feeding the world’s population.[10]

already today we witness massive

impacts of the
climate crisis:

One of the main impacts of global heating is an alteration of the global water cycle: With every additional degree in global mean temperature 7% more water evaporate from Earth’s oceans. This raised volume of water vapor in the atmosphere (with 85% water vapor is the most common of the naturally occurring greenhouse gases) leads to changes in worldwide precipitation patterns. As a new rule of thumb dry regions of Earth will get drier with climate change, while wet regions will get wetter. Whereas one region experiences extreme weather events like deluges, floods, and storm surges more frequently, in another heatwaves, droughts, and resulting wildfires occur more often and become more intense. Besides other consequences this also heavily affects agriculture and endangers food security due to increasing crop failures. And that when agriculture already has to combat extensive soil degradation due to industrial agro-practices in many parts of the world. As a consequence, in most cases agricultural lands are simply expanded at the cost of (rain)forests, the great biodiversity hotspots on Earth. In other sensitive ecosystems and harbors of biodiversity like coral reefs and alpine regions increasing temperatures (and direct absorption of CO2 into the seas which causes ocean acidification) lead to relocations or utter destruction of habitats of many animal and plant species. An increasing number of species cannot withstand such »system stress« for long, their populations shrink, collapse, and ultimately they become extinct.

Over the last few decades these interdependent sources of stress have triggered the sixth mass extinction in Earth’s long history. In contrast to the »Big Five« extinction events of the past 4.5 billion years, today it is mankind who is solely responsible for the massive loss of biodiversity we are experiencing: During the past 50 years populations of wild vertebrate animals have declined by 60% [11], and already one of 8.7 million animal and plant species worldwide face extinction within the next few decades.[12] This loss of biodiversity is one of the planetary boundaries, which man has crossed and overdrawn by far (see »Biosphere Integrity« in the graphic).[13] Another such overdrawal can be seen in the runoff of chemical fertilizers from agricultural soils into watercourses and then on into the seas, where they produce coastal hypoxic (= oxygen-depleted) deadzones, in which most marine life cannot survive. This human overloading of the natural nitrogen (N) and phosphorus (P) cycles is literally changing our planet’s chemistry today (see »Biogeochemical Flows« in the graphic).

With all the pressures that humanity is exerting on the environment today, nature’s resilience is already seriously weakened. Elements of the Earth System, which have been evolving over millions of years and very much depend on each other to function, are today nearing tipping points, which could cause them to completely change their behavior [14]: the melting of Earth’s great ice masses (the ice sheets of Greenland and Antarctica, Arctic sea-ice, and alpine glaciers all over the world) not only leads to rising sea-levels around the globe but also to changes in global air, water vapor, and sea-water circulation patterns (polar jetstream, thermohaline circulation in the Atlantic, Monsoon rains, El Niño). These in turn have considerable influence on the vegetation zones and large-scale ecosystems on Earth (boreal forests, rainforests, coral reefs) as well as on the enormous amounts of frozen methane stored in permafrost soils. With each additional tenth of a degree of global heating the risks of pushing tipping elements to and beyond their thresholds rise exponentially. Once the tipping of one element triggers another all by itself, and so-called tipping cascades occur, mankind will quickly lose all control over how the climate crisis and our living planet will evolve.
In order to reduce such risks as far as possible, in 2015 the world community adopted the groundbreaking Paris Agreement, which aims to limit global heating to 1.5 °C above preindustrial levels. But at current, still increasing rates of annual greenhouse gas emissions (2019: 37 billion tonnes CO2) the remaining carbon budget to achieve that goal (currently ca. 300 billion tonnes CO2) will be spent within less than eight years from now . . .

but the world is full of

solutions in the
here and NOW

Solutions and measures to effectively combat the climate crisis have not only been evident for quite some time now—during the past 20 years they have also become commercially competitive and ready to be deployed at scale. Therefore a growing number of concerned Earth citizens, youth movements like Fridays for Future, NGOs, green businesses, parts of the financial sector, and progressive political forces demand immediate implementation of such measures, which can be subsumed under the term »Green New Deal«:

• An energy revolution driven by a massive buildup of renewable energy capacities (solar, wind, water, geothermal) but also by an »efficiency revolution« (with a possible five-fold increase in energy efficiency across the board). A phase-out of fossil fuel use (and fossil fuel subsidies) not only in electricity generation (electricity only accounts for 20% of end-use energy) but more importantly in the transportation sector and in industrial production (hydrogen from wind-powered electrolysis will be the main avenue by which to achieve this). As a byproduct, these measures will create millions of new green jobs.

• An adoption of circular economy principles in all economic and societal sectors will allow for a dearly needed decoupling of economic development from resource use. »Perpetual economic growth« has to be debunked as a neoliberal myth, one which is becoming increasingly absurd in the face of clearly exceeded planetary boundaries.

• A transitioning away from globalized industrial agriculture and its enormously resource-sqandering practices of meat and dairy production (creating disproportionately little caloric value) and towards localized, small-scale organic agriculture, which will allow for feeding an ever-growing world population with primarily plant-based diets.

• Afforestation and reforestation are at present the most effective measures for capturing and sequestering excess carbon from the atmosphere.

• The most crucial measure though regards the point in time, at which the aformentioned solutions have to be implemented: the time to ACT is NOW! Mid-term goals for reducing greenhouse gas emissions until 2030 or 2050 will become pointless, if by then we have long spent the remaining carbon budget that would allow for a limiting of global heating to 1.5 °C, and concurrently reducing the risks of losing all control over the further evolution of the climate crisis. At current emission rates this »point of no return« will be reached in less than eight years . . . »What then?« will be the wrong question – »What NOW?« is the right one.
  
  If you want to know more about the science, causes, and impacts of the climate crisis, as well as solutions to it, take a look at the book . . .