The prime minister of Australia Malcolm Turnbull is to be replaced by Scott Morrison, after a successful leadership challenge, the Guardian reports. Amid his departure, the outgoing prime minister has commented that climate change policy is “very hard” for the Liberal-National Coalition because it is treated as an ideological matter with “bitterly entrenched” views, the Guardian writes, in a separate piece. Speaking at his final press conference this morning, Turnbull warned: “In terms of energy policy and climate policy, I think the truth is that the Coalition finds it very hard to get agreement on anything to do with emissions…The emissions issue and climate policy issues have the same problem within the Coalition of…bitterly entrenched views that are actually sort of more ideological views than views based, as I say, in engineering and economics.” Turnbull goes on to compare the issue of climate change to same-sex marriage, in that they were both seen as an “insoluble problem” for the Coalition that his government had been “able to sort out”. Scott Morrison, Australia’s incoming prime minister, was treasurer in Turnbull’s administration. Last year, the Huffington Post reported that Morrison held up a piece of coal in parliament and claimed it was a “sustainable” source of energy. A profile of Morrison in the Guardian notes that: “Morrison has generally avoided talking about his position on climate change. He’s been a public backer of Turnbull’s national energy guarantee, the policy that finally doomed him, as has his the new deputy leader, Josh Frydenberg.” Elsewhere, Reuters reports that Australia faces increased blackout risks this summer as its coal plants age.

Europe is facing an increasing threat of tropical disease outbreaks, as rising temperatures cause illnesses brought by travellers to spread more effectively, according to the European Centre for Disease Prevention and Control (ECDC). This summer has seen a spike in incidences of West Nile infections, compared to the past four years, due to an early start to the transmission season caused by high temperatures followed by wet weather – conditions ideally suited to mosquito breeding. The countries affected by the spike include Greece, Italy, Hungary and Romania. Prof Jan Semenza, who leads on scientific assessment for the ECDC, commented: “We are all a bit taken aback about how fast these change are coming down the pipeline…We are seeing more and more of these extreme weather events.”

The US Army has expanded its investments in solar power despite the current US administration’s scepticism of renewable energy, the Financial Times reports. Michael McGhee, who leads the US Army’s Office of Energy Initiatives, told the paper: “What we are looking at when we see renewables is a self-resupplying power source.” He went on to explain that installing solar panels at army bases could improve resilience against natural disasters or attacks, as well as providing cost-effective electricity. “With power grids facing threats from cyber and physical attacks as well as extreme weather, the army is seeking to provide resilient local electricity supplies for more of its bases”, the Financial Times writes. The US army added around 94MW of capacity from renewables in the fiscal year to 2016, increasing its total by 59%.

Mayors from 19 cities have pledged to make all new buildings ‘net-zero carbon’ by 2030 and upgrade existing buildings to net zero standards by 2050. Representing approximately 130 million people, the cities involved include London, New York, Copenhagen, San Jose, Sydney, Toronto and Tokyo. The declaration, which was organised by the C40 group of cities, states that net zero buildings use energy ultra-efficiently and meet any remaining energy needs from renewable sources, Energy Live News reports.

A feature in the New York Times investigates the potential implications of the Trump administration’s recent proposals to lower the social cost of carbon, as well as how they arrived at a new estimate. “When federal agencies calculate the costs and benefits of climate regulations, they use a figure called the ‘social cost of carbon'”, explains Brad Plumer. The Trump administration has tried to argue that each ton of CO2 emitted in 2020 would only cause around $1-$7 in economic damages – far lower than the Obama administration’s estimate, which was roughly $50, after adjusting for inflation. This could have major consequences, Plumer argues: “If the Trump administration can successfully claim that carbon dioxide causes relatively little harm to the economy, then it can more easily justify moves like replacing the Clean Power Plan”. Plumer notes that, “whatever number the Trump administration ultimately comes up with, they will have to defend it in court”. Last year Carbon Brief published an in-depth Q&A on the social cost of carbon.

Scott Morrison is to become the country’s sixth premier in little over a decade, but this political instability “is not the result of economic problems”, argues an editorial in the Financial Times. Instead, the paper writes, the troubles stem from “dysfunction in political institutions, a shock jock rightwing media and a shift to a US Tea Party-style populism within the ruling Liberal party”, which has resulted in “an alarming inability to tackle Australia’s biggest issue: energy and climate change”. “Even as Australia exports billions of dollars of coal and liquefied natural gas every year to Asia’s fast-growing economies, the government has struggled to keep the lights on at home”, the Financial Times explains. Meanwhile, “progressives and conservatives have fought for almost two decades over how to tackle climate change and shift a coal-dependent energy sector towards cleaner power”, and with this political uncertainty “power companies say they cannot justify long-term investment in new generation or storage”. Australia “energy wars” re-erupted on Monday when conservative backbenchers objected to emission reduction targets the Australia signed up to in the Paris Agreement. All this is “especially ill-timed”, as “Australia faces its worst drought in a century and a third of corals on the Great Barrier Reef recently died due to raised sea temperatures”.

In response to greenhouse‐gas forcing, global climate models predict a range of surface warming patterns. To better understand the sources of uncertainty in predicted warming patterns, this paper used an idealized climate model that links regional physical processes to warming responses across latitudes by representing changes in poleward atmospheric heat transport. They find that uncertainty in the spatial pattern of warming primarily arises from uncertainty in climate feedbacks, with uncertainty in climate forcing and ocean heat uptake playing smaller roles. Cloud feedbacks, in particular, contribute the greatest source of warming uncertainty in most regions. Feedback uncertainty in the tropics leads to warming uncertainty at all latitudes, while feedback uncertainty in polar regions leads to warming uncertainty that is confined near the poles. The results suggest that polar warming is particularly difficult to predict because it is influenced by both local and nonlocal feedback processes. On the other hand, improved understanding of tropical cloud feedbacks has the potential to improve warming projections at all latitudes.

On interannual to decadal timescales, the climate variability with many of the strongest societal impacts is the El Niño ‐ Southern Oscillation (ENSO). However, quantifying ENSO’s changes in a warming climate remains a formidable challenge, due to both internal variability and the complexity feedbacks in the tropical Pacific Ocean. This work uses a large ensemble of climate simulations to show that anthropogenic climate change can produce systematic increases in ENSO teleconnection strength over many land regions, driving increased interannual variability in regional temperature extremes and wildfire frequency. The intensification in temperature extremes occurs mainly over land regions and independently of changes in eastern Pacific sea surface temperature variability. Land atmosphere feedbacks are likely to play a key role in the simulated amplification, with relevance to impacts such as heat waves and wildfire frequency. This suggests that in addition to changes in the overall likelihoods of heat and wildfire extremes, the variability in these events may also be a robust feature of future climate change.