Guest Post: The human role in Australia's ‘angry’ hot summer

Image: This extraordinary photograph of the bushfires engulfing the small Tasmanian town of Dunally in January 2013 shows Tammy Holmes, second from left, clutching her two small grandchildren, two-year-old Charlotte Walker, left, and four-year-old Esther Walker. Clinging precariously to a wooden jetty are Liam Walker, nine, Matilda, 11, second from right, and six-year-old Caleb Walker. Behind them are walls of flame, the sky a lurid and demonic orange.

The human role in our ‘angry’ hot summer

By Sophie Lewis, University of Melbourne and David Karoly, University of Melbourne

Today we released a study that shows quantitatively that anthropogenic climate change substantially increased the likelihood of the record-breaking Australian summer of 2013. Indeed, human influences on the climate system increased the chances of our record hot, “angry” summer by more than five times.

Average temperatures across the globe are now 0.8°C warmer than a century ago. This shift in the average climate can lead to substantial changes in the frequency and severity of extreme climate events.

Globally, many of the record-breaking heatwaves and extreme summer temperatures occurring elsewhere have been linked to anthropogenic influences. Our latest analysis of the 2013 extreme Australian summer also demonstrates a strong human influence on the record temperatures.

Alberta Floods highlight a more active water cycle with climate change

An intense rainfall and storm event on June 20-21 has caused widespread flooding in the Canadian province of Alberta, encompassing much of the southern portion of the province including Canada's fourth largest city of Calgary. It is the worst flooding event in Alberta's recorded history, highlighting the more active hydrological cycle with climate change.

Over 120,000 people across the region were evacuated, 75,000 in Calgary (7% of the population), many now returning to flood damaged homes and businesses to start the clean up.

I am not going to say climate change caused the flooding. Clearly natural weather variability still plays a significant part in extreme weather events. But the reality is we have warmed the atmosphere and changed the base climate from which all extreme weather events are generated from. We are now living with weather in a more active hydrological cycle resulting in more frequent and intense storm events with a capacity to cause greater flooding.

IEA: Four measures to limit carbon emissions and Global Warming to 2 degrees Celsius

The International Energy Agency warned of the danger of exceeding the 2 °C of global warming unless governments take swift action to reign in emissions. The latest World Energy Outlook special report launched on the 10 June 2013 estimates global carbon dioxide (CO2) emissions in 2012 achieved a 1.4% increase, reaching a record high of 31.6 gigatonnes (Gt).

Over the last few years the International Energy Agency has consistently warned we need a Bold change of direction globally to meet climate commitments. Scientific studies show that we need to peak emissions this decade to meet 2 °C temperature goal.

With the launch of the IEA latest report - Redrawing the Energy-Climate Map - the organisation outlined four stopgap measures that can be taken to lower global energy-related greenhouse-gas emissions in the short term by 2020 to make limiting global warming to 2 °C still achievable.

Wildfires set new destructive records in Colorado and New Mexico due to climate change

High temperatures, high winds and low humidity are contributing to extreme fire weather across the US southwest. In Colorado the Black Forest fire burning north east of Colorado Springs has become the most destructive fire on record for the state destroying at least 379 homes and killing two people. Over the border the Whitewater Baldy Complex fire in the Gila National Forest has become the largest wildfire in New Mexico's recorded history. For several years scientists have indicated that Climate change is a primary cause driving the increase in the length of the fire season, the frequency and intensity of wildfires.

Reports from Colorado confirm that the Black Forest fire has so far burned 15,700 acres; 38,000 people and 13,000 homes evacuated; with the fire only 5% contained. 379 homes have been destroyed and a further 9 damaged. The damage exceeds the record destruction last year from the Waldo Canyon Fire which destroyed nearly 350 homes and also killed two people. Another Colorado wildfire near Royal Gorge has burnt 3,100 acres, destrying 20 structures and is just 20% contained.

Over the border in New Mexico the Whitewater Baldy Complex fire continues to burn in the Gila National Forest. It is the largest wildfire in New Mexico's recorded history. Started by a lightning strike on May 15th 2013, the fire has burned almost 280,000 acres and is assessed as only 37% contained one month later in mid June. High temperatures, low humidity and moderate winds continue to feed the fire. Fire fighters are focussed on containing the southern boundary of the fire. Costs of fighting this blaze have now exceeded $22 million.

Climate change is driving the increased destruction of wildfires with US Forest Service Chief Thomas Tidwell warning of more extreme wild fires in testimony to the US Senate Energy and Natural Resources Committee last week.

In 2012 wildfires burned a record 9.2 million acres in the U.S., with this year also likely to set exceptional fire records.

Mayor Bloomberg launches $20 billion climate adaptation strategy for New York

In a bold statement on June 11, 2013 from a former Naval Yard on Staten Island that was flood damaged by Ex-Tropical Cyclone Sandy, Michael Bloomberg, the Mayor of New York, launched a plan of climate adaptation and resilience for the city.

Much of the adaptive defences being planned are to prevent damage from future storms, rising seas and storm surge projected for the next century.

Flood resistance and resilience of buildings and essential services was also emphasised, including measures elevating or protecting critical building equipment, fire protection systems, electrical equipment, heating, ventilation and air conditioning systems.

But more than preparing for the next super storm, Bloomberg emphasised the importance of building resilience and preparedness for a range of climate related extreme weather disasters from "droughts, heavy downpours like we had last week, and heat waves, which may be longer, and more intense, in the years to come."

Climate change driving California native Freshwater fish species to extinction

Eighty two percent of native freshwater fish species in California, including salmon, are likely to become extinct on present trends within the next century due to climate change, reports a study lead by Professor Peter Moyle from University of California Davis.

The study - Climate Change Vulnerability of Native and Alien Freshwater Fishes of California: A Systematic Assessment Approach - found that, of 121 native fish species, 82 percent are likely to be driven to extinction or very low numbers as climate change speeds the decline of already depleted populations. In contrast, the study reported that 19 percent of the 50 non-native fish species in the state face a similar risk of extinction. Many non-native fish are likely to thrive in changed aquatic conditions, mostly at the expense of native species.

"If present trends continue, much of the unique California fish fauna will disappear and be replaced by alien fishes, such as carp, largemouth bass, fathead minnows and green sunfish," said Peter Moyle, a professor of fish biology at UC Davis who has been documenting the biology and status of California fish for the past 40 years.

"Disappearing fish will include not only obscure species of minnows, suckers and pupfishes, but also coho salmon, most runs of steelhead trout and Chinook salmon, and Sacramento perch," Moyle said.

Frogs, Salamanders, turtles declining rapidly in US due to climate change and habitat loss

A recent study revealed amphibian declines are occurring much more rapidly and more widespread than expected in species populations across the United States, even in protected national parks and wildlife refuges.

"This new study confirms that our country's amphibians are facing an extinction crisis that demands aggressive action to tackle threats like habitat destruction and climate change," said Collette Adkins Giese, a Center for Biological Diversity biologist and attorney focusing on protection of amphibians and reptiles. "Scientists have known for a long time that frogs, toads and salamanders are in big trouble, but the declines this study documents are surprising and disturbing."

US Forest Service Chief warns of more extreme wild fires associated with climate change

Wild fires are getting bigger and burning with greater intensity with an extended fire season, due in large part to climate change, according to testimony this week of Thomas Tidwell, Head of the US Forest Service to the US Senate Energy and Natural Resources Committee.

In his statement on Tuesday to the Senate Committee Tidwell said:

Around the world, the last two decades have seen fires that are extraordinary in their size, intensity and impacts. In Australia in 2009, the Black Saturday Bushfires killed 170 people. Domestically, Florida, Georgia, Utah, California, Texas, Arizona, New Mexico and Colorado, have all experienced the largest and/or the most destructive fires in their history just in the last six years. On average wildfires burn twice as many acres each year as compared to 40 years ago, and there are on average seven times as many fires over 10,000 acres per year.

In 2012 over 9.3 million acres burned in the United States. The fires of 2012 were massive in size, with 51 fires exceeding 40,000 acres. Of these large fires, 14 exceeded 100,000 acres. The increase in large fires in the west coincides with an increase in temperatures and early snow melt in recent years. This means longer fire seasons. The length of the fire season has increased by over two months since the 1970s.

Soil Carbon sequestration limited in mitigating fossil fuel emissions say scientists

Rebuilding soils through carbon sequestration and mitigating fossil fuel emissions sounds like a win-win solution all around. A reason the Liberal and National Parties in Australia adopted it as a major part of their 2010 Direct Action climate change policy. But a new international study by Australian and UK scientists said soil carbon programs while important, have many limitations, and provide too much false hope in mitigating emissions from fossil fuels.

"The capacity of terrestrial ecosystems to store carbon is finite and the current sequestration potential primarily reflects depletion due to past land use. Avoiding emissions from land carbon stocks and refilling depleted stocks reduces atmospheric CO2 concentration, but the maximum amount of this reduction is equivalent to only a small fraction of potential fossil fuel emissions." (Untangling the confusion around land carbon science and climate change mitigation policy, Brendan Mackey et al, 2013)