This chapter is an extension of the preceding one. It examines some scenarios of accelerating climate change and sea level rise resulting from action by two fundamental mechanisms: climate feedbacks and tipping points. Both mechanisms explain, for example, the Hothouse Earth hypothesis (Stephen et al. 2018), which has become all the more likely given the combined influence of at least five closely interconnected positive climate feedback mechanisms on the magnitude and speed of warming. One aspect of these climate feedbacks deserves special attention: the ongoing processes that release carbon, especially methane, into the atmosphere at high latitudes. Some studies in recent years project melting of the permafrost (land and subsea) that will be faster, if not much faster, than previously supposed. Climate feedback loops and tipping points also accelerate sea level rise. Currently (2012–2017), we observe a global mean sea level (GMSL) rise of 5 mm per year. How much the GMSL rise will be by 2030, 2050, and 2100 is uncertain. In 2017, NOAA raised the upper limit of this rise to 24 cm, 63 cm, and 2.5 meters, respectively. Hansen et al. (2016) project a GMSL rise of “several meters over a timescale of 50–150 years,” based primarily on the amplifying feedbacks caused by ongoing thawing in Antarctica and Greenland. It is now estimated (CoastalDEM) that land currently home to 300 million people will fall below the elevation of an average annual coastal flood by 2050.

It would appear not . - 2022 -------- via https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3574335/ Abstract Environmental problems have contributed to numerous collapses of civilizations in the past. Now, for the first time, a global collapse appears likely. Overpopulation, overconsumption by the rich and poor choices of technologies are major drivers; dramatic cultural change provides the main hope of averting calamity. Keywords: population, consumption, environment, agriculture, climate, culture Go to: 1. Introduction Virtually every past civilization has eventually undergone collapse, a loss of socio-political-economic complexity usually accompanied by a dramatic decline in population size [ 1 ]. Some, such as those of Egypt and China, have recovered from collapses at various stages; others, such as that of Easter Island or the Classic Maya, were apparently permanent [ 1 , 2 ]. All those previous collapses were local or regional; elsewhere, other societies and civilizations persisted unaffected. Sometimes, as in the Tigris and Euphrates valleys, new civilizations rose in succession. In many, if not most, cases, overexploitation of the environment was one proximate or an ultimate cause [ 3 ]. But today, for the first time, humanity's global civilization—the worldwide, increasingly interconnected, highly technological society in which we all are to one degree or another, embedded—is threatened with collapse by an array of environmental problems. Humankind finds itself engaged i

Limits to Growth: the 30 year update. World3 is one of several global models that have been generated throughout the world (Mesarovic/Pestel Model, Bariloche The World3 model is a system dynamics model for computer simulation of interactions between population, industrial growth, food production and limits in the ecosystems of the earth. It was originally produced and used by a Club of Rome study that produced the model and the book The Limits to Growth (1972). The creators of the model were Dennis Meadows, project manager, and a team of 16 researchers ...[We] come to the well-known study, Limits to Growth, published under the sponsorship of the 'Club de Rome' - an influential body of private individuals. A first attempt was made to make a complete systems analysis of the rapidly growing human-biological-resource-pollution system. In this analysis the manifold interactions between the different parts were explicitly taken into account. The conclusion was that disaster was waiting around the corner in a few decades because of resource exhaustion, pollution and other factors. Now, 35 years later, our world still exists, ... So the 'growth lobby' has laughed and proclaimed that Limits to Growth and, by extension, the environmental movements may be forgotten. This entirely misses the point. Certainly the timescale of the problems was underestimated in Limits to Growth, giving us a little more time than we thought. Moreover, during the last three decades a variety of national or collaborative international measures have been taken that have forced reductions in pollution, as we shall discuss. A shining example of this is the Montreal Protocol (1987) that limited the industrial production of fluorocarbons that damage the ozone layer and generated the 'ozone hole' over Antarctica. The publication of Limits to Growth has greatly contributed towards creating the general willingness of governments to consider such issues. Technological developments have also lead to improvements in the efficiency of the use of energy and other resources, but, most importantly, the warnings from Malthus onward have finally had their effect as may be seen from the population-limiting policies followed by China and, more hesitantly, by India. Without such policies all other efforts would be in vain. However, the basic message of Limits to Growth, that exponential growth of our world civilization cannot continue very long and that a very careful management of the planet is needed, remain as valid as ever. At least one study disagrees with the criticism. Writing in the journal Global Environmental Change, Turner notes that "30 years of historical data compare favorably with key features of the 'business-as-usual' scenario called…