Abstract

Both the mean climate state and anomalies from the mean determine the impact of extreme events, yet how models represent the latter is largely unexplored. Here, we assess skill of climate models participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6) for predicting monthly high temperature anomalies relative to monthly means over time. Models project that, as the planet warms, these high temperature anomalies will increase in subtropical regions and decrease in high latitudes. Both postive and negative biases remain largely unchanged regionally and seasonally within two historical periods, 1980–2001 and 2002–2023. Globally, models have underestimated the 22-year average monthly high temperature anomalies by 2–3% and 22-year maximum anomalies by 11–12%. If historical biases of models carry forward, the on-average 2100 extreme high temperatures in some regions and months could be greater than current projections by 3 K, and greater than 5 K for the most extreme cases.

Abstract

We explore the risk that self-reinforcing feedbacks could push the Earth System toward a planetary threshold that, if crossed, could prevent stabilization of the climate at intermediate temperature rises and cause continued warming on a “Hothouse Earth” pathway even as human emissions are reduced. Crossing the threshold would lead to a much higher global average temperature than any interglacial in the past 1.2 million years and to sea levels significantly higher than at any time in the Holocene. We examine the evidence that such a threshold might exist and where it might be. If the threshold is crossed, the resulting trajectory would likely cause serious disruptions to ecosystems, society, and economies. Collective human action is required to steer the Earth System away from a potential threshold and stabilize it in a habitable interglacial-like state. Such action entails stewardship of the entire Earth System—biosphere, climate, and societies—and could include decarbonization of the global economy, enhancement of biosphere carbon sinks, behavioral changes, technological innovations, new governance arrangements, and transformed social values.

Pretty shallow view of what is hitting limits of a finite planet.

Introduction

Extracting and processing materials is one of the most underappreciated yet powerful forces shaping our world. According to the Global Resources Outlook 2024, over half of global greenhouse gas emissions and 90% of land-use related biodiversity loss stem from resource extraction and processing.1 Yet global material use keeps growing relentlessly. Since 1970, natural resource extraction has more than tripled. Today, the total mass of human-made materials— concrete, steel, plastic and more—has surpassed the weight of all living biomass on Earth.

This deep dive explores the material foundations of our economy and wellbeing—foundations that are both indispensable and increasingly destructive. It highlights how raw materials underpin everything from food and energy to digital communication, and shows how current patterns of overuse, waste, and inequality are pushing us beyond planetary boundaries. It also lays bare the growing geopolitical tensions and environmental justice issues tied to resource dependency and scarcity.

To achieve the five extraordinary turnarounds at the heart of the vision set out in Earth for All: A Survival Guide for Humanity —eliminating poverty, reducing inequality, empowering women, transforming food systems, and realising the energy transition— materials emerge as a unifying thread. This paper explores that connection in greater depth.

This means rethinking how we use resources, shifting from linear “take-make-waste” systems toward circular economies, and ensuring fairer access to materials essential for life and for a sustainable future.