What’s the problem?

The planetary boundaries framework defines the space within which humanity can operate safely for generations to come. Today, we have exceeded six boundaries.

Emissions of toxic and long-lived substances like new organic compounds and heavy metals compromise the biosphere, ecosystems, and human health. Long unquantified, researchers recently revealed that chemical and particularly plastic pollution have reached unsafe levels and we are now way beyond this boundary. And food and drink packages alone account for 16% of all plastics ever produced.

The ozone layer protects Earth from harmful UV radiation. When it thins, skin cancer cases increase and biological systems suffer. For instance, ozone depletion hinders plant growth and agricultural productivity. The 1987 Montreal Protocol banned ozone-depleting substances in refrigerators, pesticides etc, allowing us to return within this boundary after surpassing it in the 1990s.

Humans add different kinds of aerosol particles and air pollutants to the atmosphere. Nitrogen fertilizers excessively sprayed over crops and fumes released when burning crop residues are two of them. Aerosols affect the hydrological cycle like the monsoon rains, while air pollutants cause around 800 000 premature deaths annually. The boundary for aerosol is not transgressed at the global level yet, but rising pressures are evident in large regions where emissions of air particles impact monsoon systems.

According to the IPCC, 20-30% of the carbon dioxide that humans are emitting is absorbed by oceans, dropping their pH level. As many marine animals have difficulties adapting to these acidified environments, the marine ecosystems we depend on for food supply risk collapsing. We are barely within this boundary but still can bring oceans back from the brink.

The use of fertilizers in industrial agriculture is changing the biogeochemical cycles of nitrogen and phosphorous. Since plants only absorb part of the added nutrients, the excess often wash out to and over-fertilize aquatic environments, which become eutrophic and oxygen-depleted. With the Baltic Sea, as one of many examples, heavily suffering from such nutrient pollution, this boundary is deep into the red.

Even if there is a lot of water on Earth, only a tiny fraction is available to humans and natural ecosystems on land, and its scarcity is becoming more acute. Scientists predict that more than 5 billion people could suffer water shortages in 2050. Since 2500 out of the 3000 liters of fresh water we use daily come from our food consumption, the latter is a crucial lever of change. The freshwater planetary boundary addresses both “green” water (invisible water, held in soil and plants in farms, forests etc.) and “blue” water (visible water in rivers, lakes etc) – both boundaries are considered to be transgressed.

Across the globe, humans are rapidly turning forests, grasslands, wetlands, and other land types into agricultural land. The practice transforms these ecosystems and often releases the carbon they store. Which, in turn, drives biodiversity loss and global warming. We have crossed this boundary.

The number of species in our ecosystems is decreasing by the day. Food production is the primary cause behind the present mass extinction and loss of genetic diversity, but also a victim of it. In the past 50 years, our food sources have diminished from thousands to just a few handfuls of species. Biodiversity loss is deep in the red. Another measure of our impact on nature (the biosphere) is how we affect its function, e.g., how much of the biomass produced by photosynthesis we appropriate globally, relative to pre-industrial levels. According to the research, this boundary was transgressed already during the late 19th century when global agriculture and forestry saw their first major expansions.

The more we release carbon dioxide and other greenhouse gases (GHGs) into the atmosphere, the warmer it gets on Earth. Currently, record-high temperatures cause sea ice to melt at unprecedented rates. We are in the red zone for this boundary, meaning the planet’s climate is at risk of changing forever. And the food system is the largest GHG emitter. The climate impact can both be measured as the concentration of GHGs in the atmosphere and as change in radiative forcing (a measure of how much energy is entering Earth’s atmosphere from the sun, compared to how much is leaving).