(i) It is a simple fact of existence on this planet that its ecosystems must be able to support us if we are to continue living.
(ii) Research shows that civilizations have historically collapsed when at least one of two factors - inequality and annual aggregate resource consumption - becomes excessive.
(iii) Our current global order is excessive in both of these factors. Inequality is at historic highs with ample signs of only worsening in the future, and our annual resource consumption is well beyond replacement rate alongside being projected to continue growing. In order to illustrate how dire the situation without room for doubt, I will stick to the factor of collapse due to ecological burden (which is a combination of both resource consumption pressures and climate-related externalities that cause massive disruptions) rather than the factor of inequality in this argument.
(iv) With regard to excess aggregate resource consumption rates, a common opposing argument is that the market economy has allowed us to make efficiency gains in resource utilization which should be able to address this. However, evidence shows that gains in resource-utilization efficiency are usually followed by increases in the rate of aggregate consumption of said resources. This means that increased efficiency does not offset aggregate resource consumption. Furthermore, ecological footprint data shows quite clearly that we have not been able to offset our consumption of resources with efficiency gains irrespective of theoretical arguments.
(v) A recent estimate by GFN indicated that if everyone lived like an American it would require 4.1 Earths to ecologically support that. If everyone lived like the French, it would require 2.5 Earths and so on. Crucially, the authors of the GFN study acknowledged that they had made significant underestimates of the number of Earths required because they did not include data about the sustainability of cropland such as soil erosion.
(vi) With regard to soil erosion, overall we are losing soil 10 to 40 times faster than it is being formed. If soil erosion at current rates continue, globally we are projected to run out of top soil in 60 years. This would result in an existential crisis for global agriculture, which is the lifeblood for civilization. One proposed solution to this is hydroponics, which is a kind of agricultural method that does not use soil. However, hydroponics cannot be a replacement for conventional agriculture because of intrinsic problems with scale and cost. It will not save civilization from a top soil crisis.
(vii) Additionally, our human activity has kicked off the extinction of multiple species that are crucial to our survival. One example is the extinction of bees (something that is well under way), which are crucial for our food production: 70 of the 100 crop species that provide 90% of our food are dependent on bees for pollination.
(viii) Aside from all of the above, climate change is an independent factor that could threaten civilization - one of the most critical problems is the rapid decline of phytoplankton populations, which (among other crucial contributions) produce the majority of the Earth's oxygen. A common argument is that we can evade the catastrophic consequences of climate change by switching from fossil fuels to alternative energy sources. There are several problems with this argument: 1.) It is unlikely that a complete decarbonization is feasible. 2.) It is highly unlikely that we will even be able to stay within the 2 degrees Celsius goal of the Paris Climate Accords. 3.) The amount of CO2 that has already been emitted and its implications for the climate are dire.
(ix) The combination of lethal challenges outlined above that civilization faces over the coming century, is likely to engineer the collapse of civilization globally.