Latest news with #ClimaMeter
The Independent
26-05-2025
- Climate
- The Independent
Deadly Australian floods were made worse by climate crisis and such storms are no longer ‘natural', scientists warn
The deadly floods that swept across New South Wales this week were intensified by the climate crisis, scientists said even as tens of thousands of people remained cut off. At least five people died and over 10,000 properties were damaged in what Australian officials described as one of the worst floods in recent memory. The worst-hit areas included the Mid North Coast and the Northern Rivers, where some towns were submerged for days and key infrastructure was washed away. The floods, sparked by days of incessant rain, submerged town intersections and street signs and covered cars up to their windshields after fast-rising waters burst riverbanks. At their peak, the floods isolated some 50,000 people. Meteorologists have noted that the flooding was sparked by a near-stationary trough system combined with a pool of cold upper-level air and moisture-laden easterly winds – conditions that have grown more extreme due to rising global average temperatures. An analysis by ClimaMeter, a climate monitoring initiative, found weather patterns like those driving this week's floods have become up to 15 per cent wetter than in the past, largely due to the warming atmosphere. The Climate Council, an Australian research group, also said that these kinds of disasters were no longer simply 'natural'. The latest research for Australia showed more rain was falling during extreme events, the organisation said. 'We've had back-to-back flood events since the 2019-20 fires,' said Andrew Gissing, chief executive of Natural Hazards Research Australia. 'These are compounding events for communities still in recovery; it's what we expect with people being in a constant state of disaster recovery under climate change.' Taree, one of the worst-hit towns, experienced its wettest May on record, with 427mm rainfall, more than a third of the yearly average, falling in just two days. Australia's prime minister, Anthony Albanese, acknowledged the rising frequency of these events during a visit to areas affected by the floods. Mr Albanese and New South Wales premier Chris Minns had hoped to travel to Taree, but poor conditions prevented them. 'Tragically, we are seeing more extreme weather events. They are occurring more frequently, and they're more intense,' Mr Albanese said. 'We need to acknowledge that whilst Australia has always had extreme weather events, the science told us that those events would be more frequent and would be more intense, and that is placing pressure on the system.' He also acknowledged that as the climate crisis was driving more frequent and extreme weather events, insuring homes was 'a real challenge'. He added, however, that his government was in contact with the Insurance Council of Australia. Climate scientists have long warned that Australia's east coast is becoming increasingly vulnerable to extreme rainfall and coastal flooding. The New South Wales government notes that sea surface temperatures in the Tasman Sea, now above average, are fuelling the moisture levels feeding intense storms. Emergency crews have rescued hundreds of people in recent days, but nearly 50,000 residents remain isolated due to flooded roads and damaged infrastructure. The full scale of the damage is still being assessed. Conditions have improved since Friday in the affected areas, but damage assessment is still underway.
Sydney Morning Herald
24-05-2025
- Science
- Sydney Morning Herald
The NSW floods have already been linked to climate change. Scientists are debating if that's too quick
'Traditional attribution studies, while thorough, often come out months after an event, missing the window when public attention and policy discussion are most active,' Faranda says. Another major player is World Weather Attribution, which so far has conducted eight attribution studies this year, including for the Los Angeles fires in January, South Korean bushfires in February, and a Central Asia heatwave in March. Loading Other organisations, including Australia's Bureau of Meteorology, are also actively researching how to attribute individual events to climate change. The attribution studies can be rapid because the methodology is peer-reviewed in advance, and the figures are plugged in for specific events. However, King says it works better for extreme heat than rainfall. When asked about studies released within days, King says: 'In terms of making general statements around the role of climate change, it is possible to do it fairly quickly. In terms of having such precise numbers, it's a bit ambitious.' He says the reason is that some methodologies can be used during or immediately after an event, while others require a lag to collect the right data. The most robust studies use multiple methodologies, which is why World Weather Attribution's studies come out weeks – rather than days – after an event. Faranda says ClimaMeter uses a well-established method of comparing recent weather events with similar atmospheric configurations over the past four decades, distinguishing between those that occurred between 1950 and 1986, and those in the more recent era from 1987 to the present. The scientists are transparent about uncertainties and always publish confidence intervals, he says. Faranda agrees that the most robust attribution studies combine different methodologies. 'ClimaMeter is one piece of the puzzle – a fast and scalable one – and we view it as a stepping stone toward more detailed studies when necessary,' he says. In their recent study on the NSW floods, Faranda and co-author Tommaso Alberti found that meteorological conditions similar to those observed during the NSW floods were up to 15 per cent wetter (an additional 3 to 4 millimetres of rain per day) and up to 0.75 degrees warmer, compared with the past. The study concludes that the extreme rainfall that caused the flooding was mainly intensified by human-induced climate change, with natural variability playing a secondary role, and that adaptation was necessary. University of Melbourne Professor Emeritus David Karoly, an international climate expert affiliated with the Climate Council, has some concerns about the methodology. 'This was done too quickly, in some sense, to be careful about what was relevant,' says Karoly. 'It was probably a too-rapid attribution analysis.' Karoly, who has contributed to IPCC (Intergovernmental Panel on Climate Change) reports, has sat on the Climate Change Authority and headed up science research for CSIRO, says he wrote to the ClimaMeter scientists earlier in the year to outline his concerns about the Cyclone Alfred attribution study, but did not receive a reply. In that case, his criticism was that it was impossible to find similar events in the window from 1987 to today since there had not been a tropical cyclone (or ex-tropical cyclone) as far south as Brisbane in that time. Loading Last week's attribution study for the NSW floods looked at events with similar surface pressure patterns – the arrangement of high- and low-pressure areas depicted as isobars on weather maps. With the Southern Annular Mode positive, as reported by this masthead, those pressure systems are bringing onshore flows of moist air from the ocean. However, Karoly says the primary driver of Taree's extreme rainfall last week was thunderstorms and upper-level disturbance in the atmosphere. Faranda acknowledges that localised processes such as thunderstorms can add complexity that is not fully captured by ClimaMeter's methods, and says the team's goal is to be transparent about its limitations. He says he did not receive Karoly's earlier email and would be happy to speak to the professor. Despite his quibbles, Karoly said the conclusion of the ClimaMeter study is sound because it matches the warning from the IPCC that extreme rainfall events are intensifying with global warming, as well as the regional observational data in the Bureau of Meteorology and CSIRO's 2024 State of the Climate report.
The Age
24-05-2025
- Science
- The Age
The NSW floods have already been linked to climate change. Scientists are debating if that's too quick
'Traditional attribution studies, while thorough, often come out months after an event, missing the window when public attention and policy discussion are most active,' Faranda says. Another major player is World Weather Attribution, which so far has conducted eight attribution studies this year, including for the Los Angeles fires in January, South Korean bushfires in February, and a Central Asia heatwave in March. Loading Other organisations, including Australia's Bureau of Meteorology, are also actively researching how to attribute individual events to climate change. The attribution studies can be rapid because the methodology is peer-reviewed in advance, and the figures are plugged in for specific events. However, King says it works better for extreme heat than rainfall. When asked about studies released within days, King says: 'In terms of making general statements around the role of climate change, it is possible to do it fairly quickly. In terms of having such precise numbers, it's a bit ambitious.' He says the reason is that some methodologies can be used during or immediately after an event, while others require a lag to collect the right data. The most robust studies use multiple methodologies, which is why World Weather Attribution's studies come out weeks – rather than days – after an event. Faranda says ClimaMeter uses a well-established method of comparing recent weather events with similar atmospheric configurations over the past four decades, distinguishing between those that occurred between 1950 and 1986, and those in the more recent era from 1987 to the present. The scientists are transparent about uncertainties and always publish confidence intervals, he says. Faranda agrees that the most robust attribution studies combine different methodologies. 'ClimaMeter is one piece of the puzzle – a fast and scalable one – and we view it as a stepping stone toward more detailed studies when necessary,' he says. In their recent study on the NSW floods, Faranda and co-author Tommaso Alberti found that meteorological conditions similar to those observed during the NSW floods were up to 15 per cent wetter (an additional 3 to 4 millimetres of rain per day) and up to 0.75 degrees warmer, compared with the past. The study concludes that the extreme rainfall that caused the flooding was mainly intensified by human-induced climate change, with natural variability playing a secondary role, and that adaptation was necessary. University of Melbourne Professor Emeritus David Karoly, an international climate expert affiliated with the Climate Council, has some concerns about the methodology. 'This was done too quickly, in some sense, to be careful about what was relevant,' says Karoly. 'It was probably a too-rapid attribution analysis.' Karoly, who has contributed to IPCC (Intergovernmental Panel on Climate Change) reports, has sat on the Climate Change Authority and headed up science research for CSIRO, says he wrote to the ClimaMeter scientists earlier in the year to outline his concerns about the Cyclone Alfred attribution study, but did not receive a reply. In that case, his criticism was that it was impossible to find similar events in the window from 1987 to today since there had not been a tropical cyclone (or ex-tropical cyclone) as far south as Brisbane in that time. Loading Last week's attribution study for the NSW floods looked at events with similar surface pressure patterns – the arrangement of high- and low-pressure areas depicted as isobars on weather maps. With the Southern Annular Mode positive, as reported by this masthead, those pressure systems are bringing onshore flows of moist air from the ocean. However, Karoly says the primary driver of Taree's extreme rainfall last week was thunderstorms and upper-level disturbance in the atmosphere. Faranda acknowledges that localised processes such as thunderstorms can add complexity that is not fully captured by ClimaMeter's methods, and says the team's goal is to be transparent about its limitations. He says he did not receive Karoly's earlier email and would be happy to speak to the professor. Despite his quibbles, Karoly said the conclusion of the ClimaMeter study is sound because it matches the warning from the IPCC that extreme rainfall events are intensifying with global warming, as well as the regional observational data in the Bureau of Meteorology and CSIRO's 2024 State of the Climate report.
Sydney Morning Herald
22-05-2025
- Climate
- Sydney Morning Herald
The intensifying climate driver behind the coastal deluges and inland drought
From Queensland to the South Coast of NSW, rainfall has been unusually high. That started with Ex-Tropical Cyclone Alfred in March, which a rapid attribution study by ClimaMeter found was slower and wetter because of climate change. Climate scientists expect fewer cyclones in Australia as the planet heats up, but warn they are moving further south and carrying more rain. This week the higher rainfall has been evident with floods on the Mid North Coast of NSW. McDowell said Taree on the Mid North Coast had recorded its highest ever two-day rainfall on record in the two days to 9am Wednesday – about 400 millimetres or about a third of its typical annual rainfall. East Coast Lows – which can be influenced by a positive SAM – have also caused widespread coastal erosion, with beaches on the Central Coast still denuded of sand after high swells in April. Climate change is increasing the amount of moisture the atmosphere can hold by about 7 percentage points of humidity for every degree of warming. Already, global humidity has increased 7 percentage points over the past few decades alongside one degree of warming. Scientia Professor Matthew England, a climate expert at the University of NSW, said the marine heatwave in the oceans around Australia would also contribute to the intensity of rainfall. 'We know that onshore winds pick up moisture from the ocean, and that warmer oceans drive increased atmospheric moisture and humidity, so we can expect that as our oceans warm, this effect will be enhanced,' England said. Loading 'The temperatures in the Tasman Sea have been well above average for the past few years, so some of this increased coastal rainfall could be due to those warmer ocean temperatures.' At the same time, McDowell also said the showers and rain-bearing systems blowing in from the east don't make it very far across the land mass, meaning it is abnormally dry inland. 'If you look at April, or the whole of March and April, you've got parts of Victoria, NSW, South Australia and Tasmania that have the lowest rainfall on record, so it's pretty unusual,' McDowell said. 'In the past 30 years or so, we've seen [the Southern Annular Mode in positive] becoming more frequent … and there's potential that this is a climate change signal.' England said the recent trends for a positive SAM 'have been driven by both increasing greenhouse gases and ozone depletion'. 'Both act to alter atmospheric pressure fields in such a way that the jet stream intensifies and shifts poleward, making the SAM more positive,' England said. (The jet stream is a band of powerful high-altitude winds that encircle the globe). 'While the ozone hole is recovering, we expect ongoing positive trends in the SAM due to increasing greenhouse gases.' Dr Chiara Holgate in the ARC Centre of Excellence for Weather of the 21st Century at the Australian National University, said Australia had a highly variable climate, and without an attribution analysis, it was impossible to say that climate change was the cause of any particular drought or floods. At the same time, Holgate said people currently experiencing drought should expect more of it. 'The area of southern Australia that is at the moment drought-affected pretty closely resembles the parts of Australia that are projected to experience more drought in the future with climate change,' Holgate said. 'Unless emissions are cut drastically, the current science is saying that this part of Australia is expected to see more frequent and longer droughts in the future.' Heading into winter, rain could be on the way. The weather bureau's long-term outlook suggests the east coast and inland Australia have a strong likelihood of higher rainfall than usual, especially in August. McDowell said the main reason was that global climate models, including the one used by BoM, predicted the Indian Ocean Dipole to become negative in winter, meaning more rainfall was likely for inland Australia. The uncertainties of the long-range outlook meant it should be taken with 'a pinch of salt', he added.
The Age
22-05-2025
- Climate
- The Age
The intensifying climate driver behind the coastal deluges and inland drought
From Queensland to the South Coast of NSW, rainfall has been unusually high. That started with Ex-Tropical Cyclone Alfred in March, which a rapid attribution study by ClimaMeter found was slower and wetter because of climate change. Climate scientists expect fewer cyclones in Australia as the planet heats up, but warn they are moving further south and carrying more rain. This week the higher rainfall has been evident with floods on the Mid North Coast of NSW. McDowell said Taree on the Mid North Coast had recorded its highest ever two-day rainfall on record in the two days to 9am Wednesday – about 400 millimetres or about a third of its typical annual rainfall. East Coast Lows – which can be influenced by a positive SAM – have also caused widespread coastal erosion, with beaches on the Central Coast still denuded of sand after high swells in April. Climate change is increasing the amount of moisture the atmosphere can hold by about 7 percentage points of humidity for every degree of warming. Already, global humidity has increased 7 percentage points over the past few decades alongside one degree of warming. Scientia Professor Matthew England, a climate expert at the University of NSW, said the marine heatwave in the oceans around Australia would also contribute to the intensity of rainfall. 'We know that onshore winds pick up moisture from the ocean, and that warmer oceans drive increased atmospheric moisture and humidity, so we can expect that as our oceans warm, this effect will be enhanced,' England said. Loading 'The temperatures in the Tasman Sea have been well above average for the past few years, so some of this increased coastal rainfall could be due to those warmer ocean temperatures.' At the same time, McDowell also said the showers and rain-bearing systems blowing in from the east don't make it very far across the land mass, meaning it is abnormally dry inland. 'If you look at April, or the whole of March and April, you've got parts of Victoria, NSW, South Australia and Tasmania that have the lowest rainfall on record, so it's pretty unusual,' McDowell said. 'In the past 30 years or so, we've seen [the Southern Annular Mode in positive] becoming more frequent … and there's potential that this is a climate change signal.' England said the recent trends for a positive SAM 'have been driven by both increasing greenhouse gases and ozone depletion'. 'Both act to alter atmospheric pressure fields in such a way that the jet stream intensifies and shifts poleward, making the SAM more positive,' England said. (The jet stream is a band of powerful high-altitude winds that encircle the globe). 'While the ozone hole is recovering, we expect ongoing positive trends in the SAM due to increasing greenhouse gases.' Dr Chiara Holgate in the ARC Centre of Excellence for Weather of the 21st Century at the Australian National University, said Australia had a highly variable climate, and without an attribution analysis, it was impossible to say that climate change was the cause of any particular drought or floods. At the same time, Holgate said people currently experiencing drought should expect more of it. 'The area of southern Australia that is at the moment drought-affected pretty closely resembles the parts of Australia that are projected to experience more drought in the future with climate change,' Holgate said. 'Unless emissions are cut drastically, the current science is saying that this part of Australia is expected to see more frequent and longer droughts in the future.' Heading into winter, rain could be on the way. The weather bureau's long-term outlook suggests the east coast and inland Australia have a strong likelihood of higher rainfall than usual, especially in August. McDowell said the main reason was that global climate models, including the one used by BoM, predicted the Indian Ocean Dipole to become negative in winter, meaning more rainfall was likely for inland Australia. The uncertainties of the long-range outlook meant it should be taken with 'a pinch of salt', he added.
