An Inconvenient Tree: Is Climate Change Driving Worse Floods?

Essay by Eric Worrall

Does evidence of past extreme floods invalidate claims that climate change is making floods worse?

Picture of tree at centre of furious flood debate

A seemingly simple picture of a tree in regional Australia has sparked a furious climate change debate.

Staff writer
November 26, 2022 – 3:40PM

A picture of a tree in regional South Australia has sparked a wild climate change debate. 

Well above the current flood level is a marking from 1956. 

For some, it was a smoking gun that climate change isn’t real. 

“And the climate change back in 1956 was caused by what?” one person joked. 

“I wonder if they were talking climate change in 73, 74 and 75,” another added. 

Others pointed out an obvious issue. 

“How tall was that tree in 1956?” one person questioned.

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As Australia continues to suffer a year of devastating floods, Climate alarmists are moving to take advantage. Flannery’s Climate Council is leading the pack, pushing the narrative that climate change is responsible for more floods – which is hilarious, given a few years ago Climate Council founder Tim Flannery was pushing the narrative that we had entered a period of endless drought. “… even the rain that falls isn’t actually going to fill our dams and our river systems …” – remember saying that, Tim?

At the center of this debate is the embarrassing evidence that past floods were worse than recent floods.

Some alarmists appear to be claiming markers on South Australia’s “Tree of Knowledge” have moved due to tree growth, disputing evidence that past floods were worse. But there are plenty of inanimate historic flood markers, which appear to confirm that tree growth alone cannot account for past flood markers being higher. For example, the markers on a heritage riverfront building in the Queensland town of Maryborough (see top of page) show a spectacular flood in 1893, which far exceeds any modern floods in the region.

Having said that, we cannot conclude whether climate change is influencing Aussie floods based on this evidence, because that would be comparing apples to oranges. Since 1893 there have been substantial waterworks – irrigation channels, reservoirs and flood mitigation measures – on flood prone rivers which run through inhabited areas of Australia.

What about more scientific measurements?

The following is a slide from Professor Andy Pitman’s presentation in 2019. Pitman is Professor of Climate Extremes at the University of New South Wales. Pitman appeared to admit climate science doesn’t have a clue what CO2 is doing to long term flooding, if anything – though he later appeared to recant, alluding that climate change was making things worse in some indirect and unspecified fashion.

Link between climate change and droughtLink between climate change and droughtLink between climate change and drought
h/t JoNova – a slide from Professor Pitman’s presentation in June 2019

Could volcanic activity be a contributor to major floods in Australia? Australia is on the South Western edge of the Ring of Fire. While the Australian mainland is not very volcanically active, there have been some spectacular eruptions in our neighbourhood, such as the infamous Krakatoa eruption in 1883, or the 1815 Tambora Eruption, which is blamed for causing famine in the United States in 1816, “The Year Without a Summer”.

A notable volcanic eruption occurred at the start of 2022 – The Hunga Tonga eruption. JoNova published an intriguing comparison between the volcanic ash distribution from the Hunga Tonga eruption in January 2022, and 2022 rainfall anomalies across Australia. Hunga Tonga was light on sulphates, but the blast threw unprecedented amounts of water into the stratosphere. Where I live, on the Southern edge of the volcanic debris distribution, we’ve had some spectacular sunsets over the last year.

The apparent overlap between rainfall anomalies and volcanic debris could be a coincidence – but the comparison is visually intriguing.

Rainfall vs Volcanic Ash from Hunga TongaRainfall vs Volcanic Ash from Hunga TongaRainfall vs Volcanic Ash from Hunga Tonga
2022 Rainfall anomaly vs Ash distribution from the Hunga Tonga volcano. Source JoNova. Note I created the animation, and stretched the rainfall map to try to match the geography of the ash map, so don’t blame JoNova for the imperfect fit.

So what can we conclude from all this? Unfortunately the answer is, not a lot.

I can’t tell you what climate change is or will do to rainfall in Australia. And going by Professor Pitman’s presentation, neither can anyone else. Though having said this, even detecting a significant change would be the real challenge, given the magnitude of Australia’s climate variability across a wide range of timescales.

via Watts Up With That?

November 26, 2022 at 08:37PM

Sunday Open Thread

Sunday Open Thread

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via JoNova

November 26, 2022 at 08:28PM

Profiting From Fear

Al Gore’s Antarctic ice core graph showed the exact opposite of what he claimed. He scammed billions of schoolchildren and got rich.

via Real Climate Science

November 26, 2022 at 07:47PM

Claim: California’s Carbon Mitigation Efforts May be Thwarted by Climate Change Itself

UCI study: Higher heat will limit ecosystem’s role in removing atmospheric CO2


Research News


Irvine, Calif., July 22, 2021 – To meet an ambitious goal of carbon neutrality by 2045, California’s policymakers are relying in part on forests and shrublands to remove CO2 from the atmosphere, but researchers at the University of California, Irvine warn that future climate change may limit the ecosystem’s ability to perform this service.

In a paper published today in the American Geophysical Union journal AGU Advances, the UCI Earth system scientists stressed that rising temperatures and uncertain precipitation will cause a decrease in California’s natural carbon storage capacity of as much as 16 percent under an extreme climate projection and of nearly 9 percent under a more moderate scenario.

“This work highlights the conundrum that climate change poses to the state of California,” said lead author Shane Coffield, a UCI Ph.D. candidate in Earth system science. “We need our forests and other plant-covered areas to provide a ‘natural climate solution’ of removing carbon dioxide from the air, but heat and drought caused by the very problem we’re trying to solve could make it more difficult to achieve our objectives.”

Trees and plants draw CO2 from the atmosphere when they photosynthesize, and some of the carbon ends up stored in their biomass or the soil. California’s climate strategy depends in part on enhanced carbon storage to offset some of the emissions from transportation, power generation and other sources. The combination of this natural carbon sequestration system and measures to promote green energy is hoped to help the state reach its target of not contributing net carbon to the environment by 2045.

But the UCI scientists suggest that an even more aggressive approach to curtailing emissions may be necessary.

“The emissions scenario that we follow will have a large effect on the carbon storage potential of our forests,” said co-author James Randerson, who holds the Ralph J. & Carol M. Cicerone Chair in Earth System Science at UCI. “A more moderate emissions scenario in which we convert to more renewable energy sources leads to about half of the ecosystem carbon [sequestration] loss compared to a more extreme emissions scenario.”

Coffield said that current climate models are not in agreement about California’s future precipitation, but it’s probable that the northern part of the state will get wetter and the southern part drier. He also said that coastal areas of Central and Northern California and low- and mid-elevation mountain areas – sites of large offset projects – are the most likely to lose some of their carbon sequestration powers over the next several decades.

In addition, the researchers were able to estimate the effects of climate change on specific tree species. They project that coast redwoods will be constrained to the far northern part of their range by the end of the century and that hotter, drier conditions will favor oak trees at the expense of conifers.

While the study used statistical modeling to peer into the future of the state’s ecosystems, the research also highlights the importance of present-day drought and wildfire as key mechanistic drivers of carbon sequestration losses. Other studies have estimated that the 2012-2015 drought killed more than 40 percent of ponderosa pines in the Sierra Nevada range. Another issue the researchers describe is the loss of trees from California’s worsening wildfire situation.

“We hope that this work will inform land management and climate policies so that steps can be taken to protect existing carbon stocks and tree species in the most climate-vulnerable locations,” Randerson said. “Effective management of fire risk is essential for limiting carbon [sequestration] losses throughout much of the state.”


Joining Coffield and Randerson on this project were Kyle Hemes, from the Stanford Woods Institute for the Environment at Stanford University; Charles Koven, from the Climate & Ecosystem Sciences Division at Lawrence Berkeley National Laboratory; and Michael Goulden, UCI professor of Earth system science and ecology & evolutionary biology. The study received funding from the National Science Foundation, the UC National Laboratory Fees Research Program, and the California Strategic Growth Council’s Climate Change Research Program.

About the University of California, Irvine: Founded in 1965, UCI is the youngest member of the prestigious Association of American Universities and is ranked among the nation’s top 10 public universities by U.S. News & World Report. The campus has produced three Nobel laureates and is known for its academic achievement, premier research, innovation and anteater mascot. Led by Chancellor Howard Gillman, UCI has more than 36,000 students and offers 224 degree programs. It’s located in one of the world’s safest and most economically vibrant communities and is Orange County’s second-largest employer, contributing $7 billion annually to the local economy and $8 billion statewide. For more on UCI, visit

Media access: Radio programs/stations may, for a fee, use an on-campus ISDN line to interview UCI faculty and experts, subject to availability and university approval. For more UCI news, visit Additional resources for journalists may be found at

From EurekAlert!

via Watts Up With That?

November 26, 2022 at 05:05PM