Attribution of events, known to have happened many times before, to human causes by invoking ‘the role of climate change’ in the modern era is speculation at best, as is any vague claim that humans could ‘increase the risk’ of such events. As usual, climate alarmists want people to feel guilty and nervous.
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Most Australians have known drought in their lifetimes, and have memories of cracked earth and empty streams, paddocks of dust and stories of city reservoirs with only a few weeks’ storage, says The Conversation (via Phys.org).
But our new research finds over the last 1,000 years, Australia has suffered longer, larger and more severe droughts than those recorded over the last century.
These are called “megadroughts,” and they’re likely to occur again in coming decades.
Megadroughts can last multiple decades—or even centuries—with occasional wet years offering only brief relief. Megadroughts can also be shorter periods of very extreme conditions.
We show megadroughts have occurred several times across every inhabited continent over the last two millennia. They’ve dealt profound damage to agriculture and water supplies, increased fire risk, and have even contributed to toppling civilizations.
Unless we incorporate the full potential of Australian drought into our planning, management and design, their impacts on society and the environment will likely worsen in coming decades.
The role of climate change
Instrumental records only go back so far. In Australia, they cover only the last 120 years or so. Scientists can gauge local, yearly climate further back in time, by deciphering clues written in tree rings, corals, and buried ice (known as ice cores), among other archives.
To look at previous occurrences of megadroughts, we consolidated findings drawn from such datasets and a range of other long-term records.
Historically, droughts have been defined by rainfall deficits, and these deficits can be largely attributed to complex interactions between oceans and the atmosphere over a long time. For example, decades-long La Niña conditions have been linked to medieval droughts in North and South America.
In contrast, research suggests human-caused climate change is now playing a more important role in amplifying drought conditions, as rising global temperatures increase evaporation.
There is some uncertainty in climate models about the effect of climate change on rainfall at local and regional scales. However, climate change is putting places that have previously endured megadroughts—such as Australia—at an increased risk of megadroughts in future.
Full article here.
via Tallbloke’s Talkshop
October 9, 2022, by oldbrew
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