Climate change: Current warming ‘unparalleled’ in 2,000 years

It’s a climate emergency

Matt McGrath BBC Read full article hereThe speed and extent of current global warming exceeds any similar event in the past 2,000 years, researchers say. They show that famous historic events like the “Little Ice Age” don’t compare with the scale of warming seen over the last century.

The research suggests that the current warming rate is higher than any observed previously. The scientists say it shows many of the arguments used by climate sceptics are no longer valid….

No evidence for globally coherent warm and cold periods over the preindustrial Common Era Letter | Published: 24 July 2019

Nature volume 571, pages550–554 (2019) | Download Citation

Abstract

Earth’s climate history is often understood by breaking it down into constituent climatic epochs1. Over the Common Era (the past 2,000 years) these epochs, such as the Little Ice Age2,3,4, have been characterized as having occurred at the same time across extensive spatial scales5. Although the rapid global warming seen in observations over the past 150 years does show nearly global coherence6, the spatiotemporal coherence of climate epochs earlier in the Common Era has yet to be robustly tested. Here we use global palaeoclimate reconstructions for the past 2,000 years, and find no evidence for preindustrial globally coherent cold and warm epochs. In particular, we find that the coldest epoch of the last millennium—the putative Little Ice Age—is most likely to have experienced the coldest temperatures during the fifteenth century in the central and eastern Pacific Ocean, during the seventeenth century in northwestern Europe and southeastern North America, and during the mid-nineteenth century over most of the remaining regions. Furthermore, the spatial coherence that does exist over the preindustrial Common Era is consistent with the spatial coherence of stochastic climatic variability. This lack of spatiotemporal coherence indicates that preindustrial forcing was not sufficient to produce globally synchronous extreme temperatures at multidecadal and centennial timescales. By contrast, we find that the warmest period of the past two millennia occurred during the twentieth century for more than 98 per cent of the globe. This provides strong evidence that anthropogenic global warming is not only unparalleled in terms of absolute temperatures5, but also unprecedented in spatial consistency within the context of the past 2,000 years.

Ellie comment: From climate scientist Peter Kalmus on Twitter : “The correct “12 years” claim: We have 10 yrs, 5 months, 4 days until we must cut global emissions in half for a 50/50 chance to stay under 1.5°C of mean global heating according to IPCC SR1.5. Many scientists, including me, feel this underestimates irreversible global change.”