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Between 1911 and 2020, the time under drought across the majority of Australia decreased, a new paper published by the European Geosciences Union concluded. Some readers will be surprised by the researchers’ findings: “Australia frequently experiences severe and widespread droughts, causing impacts on food security, the economy, and human health. Despite this, recent research to comprehensively understand the past trends in Australian droughts is lacking. … Calculating trends in time and area under drought for the various drought types, we find that although there have been widespread decreases in Australian droughts since the early 20th century, extensive regions have experienced an increase in recent decades. However, these recent changes largely remain within the range of observed variability, suggesting that they are not unprecedented in the context of the historical drought events.” What is the total biomass of all mammals on the planet, and how has that figure changed over time? A new paper, from researchers in the U.S. and Israel, sought to uncover the answer. While the populations of humans and domestic animals have rapidly grown, they concluded, the total mass of wild animals has dropped twofold. “Humans have continuously increased their global range and footprint over the last ≈10,000 years. These processes accelerated considerably following technological innovations introduced in the 19th century, with the global human population growing from 1.2 billion in 1850 to the current 8 billion individuals over less than 200 years. This rapid growth in the global human population required a greater consumption of natural resources, accompanied by loss of natural habitat,” the researchers wrote. “Over the same period, human activities placed numerous pressures on wild mammal populations, including hunting, habitat loss, and many more.” Researchers at the University of Washington recently penned a study contributing to the emergent consensus that the world is on track for an increase in 21st-century temperatures of less than 3 degrees Celsius. This analysis projects an increase of 2.4°C by 2100. Perhaps most importantly, a growing body of literature suggests that extreme climate scenarios are implausible. As another recent paper by climate scientist Zeke Hausfather concludes: “Progress on both clean energy technologies and climate policies … has reduced the plausibility of high-emissions pathways.” An important consideration is that most current policy projections assume high population growth rates—for instance, the University of Washington paper bases its research on a population of 10 billion by 2100. As demographers continue to revise these estimates down, expect further moderation in climate projections.
