by Felix Creutzig
Can we rely on renewable energies and electric cars to win the climate race? Surely, such technologies will make great contributions, and, in fact, are absolutely necessary to achieve ambitious climate goals, such as the 2C target. Yet, they might not be sufficient.
In a comprehensive review, published in Annual Review of Environment and Resources, we investigate the role of the demand side to climate change mitigation. The review finds substantiative opportunities in particular in the food sector, and in cities. At least 20% counterfactual reductions in emissions can be achieved by reducing meat consumption, by modal shift and compacter urban form in urban transport, and in the building sector by behavioral change. The overall range is broad and uncertain, and higher contributions of the demand side are feasible.
Demand-side solutions fall into two (overlapping) classes: infrastructures and behavioural change. Infrastructures essentially form endogenous preferences and set the cost structures for consumption choices (think about the convenience of public transport or car driving in Manhattan and Houston). Behavioural change involves opportunities to change entrenched habits, partially also by modifying ‘soft’ infrastructures, e.g. by nudging.
The review also identifies key hurdles to perform assessment of demand-side solutions. Key among them is that conventional cost-benefit analysis is hard to carry out when preferences are not exogenously given. Then costs and benefits not only depend on given environmental outcomes of a specific intervention, but also on how preferences changed by the intervention. A comprehensive model of human behaviour is required (see figure above).
The demand side received only scarce attention in recent assessment reports and the reasons are not necessarily obvious. The technical difficulties certainly discourage quantitative assessments. Yet, given its likely importance, more studies should systematically tackle this challenge, notably learning from the experience in urban studies.
Last week saw Environmental Research Letters – environmentalresearchweb’s sister product – celebrate its tenth anniversary with a party at the AGU Fall Meeting in San Francisco, US. Editor-in-chief Dan Kammen of the University of California, Berkeley made a speech thanking the environmental research community for its support, whilst ERL guests toasted the open-access publication with cake and prosecco and were able to take away copies of the journal’s 10th anniversary collection.
Earlier in the day, Kammen had participated in an AGU session on the shifting landscape for science.
By Liz Kalaugher
The Arctic in winter is cold, dark and dangerous. So it’s no surprise that it’s not seen too much research. But in January 2015 the Norwegian Young Sea Ice Cruise embedded a research ship in the ice, in only the second expedition of its type. The first was 20 years ago when the SHEBA expedition monitored multi-year sea ice in the Pacific sector. The N-ICE expedition, in contrast, moored in the Atlantic sector north of Spitsbergen, where the ice was first- or second-year and thin.
“Lots of the things we experienced took us by surprise,” said Mats Granskog of the Norwegian Polar Institute, who was chief scientist for N-ICE, at a press conference. “We saw a new Arctic, with ice 3-4 feet thick that behaves differently.”
This ice moves more quickly, breaks up more easily and is more vulnerable to storms and winds, Granskog explained. Learning about it should improve weather forecasts in North America and Asia. This is one of the reasons the team went, Granskog said – to find out how well we know the Arctic and to determine the validity of the ice data in our climate models.
During the trip the researchers had to “battle the dark, the cold” and cope when the ice broke up under their feet and they had to rescue their equipment. “It was no simple ordeal,” Granskog said of the six-month long expedition.
Amelie Meyer of the Norwegian Polar Institute was a member of the kit rescue team. The equipment had been installed on an ice floe a few miles wide next to the ship. On the morning of the 19th June, the floe cracked. Fortunately no researchers were out on the ice at the time. Within a few hours, the floe had broken up into hundreds of pieces. “It was a bit epic,” Meyer said, describing her trips in a Zodiac boat to retrieve the instruments, many of which contained data.
As well as the unplanned rescue, the researchers also saw way more snow than expected, Granskog said. In places, the snow was so heavy that it caused the sea ice to float below the surface of the sea, inundating the bottom layer of the snow with salt-water. This phenomenon has been seen in Antarctica, where the sea ice is generally thinner and there’s more snow, but this was the first sighting in the Arctic.
Von Walden of Washington State University joined the trip to characterise atmospheric conditions. In winter, the Arctic atmosphere tends to be either clear or overcast. When clear, he found, atmospheric conditions were similar to those discovered by the SHEBA expedition.
But N-ICE also saw significant storms, carried from the south by an unusual jet stream. These storms brought large amounts of warmth and moisture to the Arctic, restricting sea ice growth, whilst the winds pushed the ice out. Early February 2015 saw the lowest ever winter sea ice extent. One storm brought a temperature rise from -40 F to 32 F in less than 48 hours, and winds of more than 50 miles per hour, as well as increasing moisture levels ten-fold.
Whilst von Walden examined the atmosphere, Meyer was there to examine conditions below the ice. The Arctic Ocean is relatively warm, she explained, with temperatures of 32 F below the ice and 40 F a few hundred feet below the surface. It’s generally calm beneath the ice, which isolates the water from the atmosphere. But the winter storms, Meyer discovered, made the ice drift so fast that it mixed the water beneath, bringing warm water up from the depths and melting the ice from below.
Algae bloomed early beneath the thin ice, the trip revealed. You might think that would absorb more carbon, Meyer said, but these algae didn’t sink well, so didn’t export carbon to the ocean depths.
by Liz Kalaugher
It’s highly likely that the world’s polar bear population, currently 26,000 strong, will decrease by a third within the next 35-40 years. That’s according to Kristin Laidre of the University of Washington, US, speaking at a press conference at the AGU Fall Meeting in San Francisco.
This finding supports the listing of polar bears as vulnerable by the International Union for Conservation of Nature (IUCN) Red List, which requires projection of species population numbers after three generations. Laidre and colleagues found that the average age of a female polar bear with dependent cubs is 11.5 years so 35 years corresponds to roughly three generations.
Polar bears use ice for traveling, hunting, mating and, in some cases, for their maternity dens. From 1979 to 2015, Arctic sea ice shrank at an average rate of 53,100 square km per year.
“When we look forward several decades, climate models predict such profound loss of Arctic sea ice that there’s little doubt this will negatively affect polar bears throughout much of their range, because of their critical dependence on sea ice,” said Laidre in a press release.
There are 19 sub-populations of polar bears around the Arctic Circle, living in 4 eco-regions. Some of these populations have never been studied whilst the number of animals in others have only been counted one or two times. Two or three populations have been studied on an annual basis, Laidre explained.
Some regions of the Arctic, such as the Chukchi Sea, are highly ecologically productive. Even though sea ice cover here has decreased, polar bears in the area are in better condition than they were 20 years ago; there could be a time lag before the full effects of the ice loss kick in. In other areas, like western Hudson Bay, polar bear survival and reproduction have declined as sea ice availability has dropped.
Laidre, Eric Regehr of the US Fish and Wildlife Service, and colleagues made their predictions by analysing sea ice extent from satellite observations and projecting this forward by 35 years. They evaluated three different relationships of polar bear numbers to sea ice – a decline proportional to the sea ice loss, and two changes based on previous data – before taking a median value across all three scenarios.
This revealed that the probability of a more than 30% reduction in polar bear numbers in the next 35-40 years is 0.71. The probability of a decrease in headcount of more than half was just 0.07.
By Liz Kalaugher
Given the option, would you help bees or worms? That’s the choice indicated by initial results presented at the European Geosciences Union General Assembly in Vienna this week by Sophie Kratschmer of the University of Natural Research and Life Sciences in Vienna.
As part of the VineDivers project, Kratschmer found that, contrary to expectations, solitary bees in vineyards in eastern Austria thrived when there was less management of the vegetation between rows of vines. This higher diversity was a surprise as disturbed ground tends to contain more flowers, a food source for bees. Since solitary bees nest underground, however, they may not appreciate tillage. The team did find a link between flower coverage and the number of wild bee species.
Earthworms, in contrast, were more diverse when there was ploughing of the earth between the vines, probably, according to Kratschmer, because it boosts the carbon content and makes the soil less compact. Plant diversity and biomass weren’t affected by the management intensity.
Both bees and worms are useful for viniculture, with bees providing pollination while earthworms help form soil and cycle nutrients.
Fortunately, when it comes to selecting management regimes for vineyards, the findings may not boil down to a difficult choice between bees and worms. Next Kratschmer will investigate a “medium” management intensity, intermediate between the low and high regimes in this study, which may work for both types of animal.
The wider VineDivers project will pool results from France, Romania and Spain and also use GIS analysis to find out the role of landscape diversity.
By Dave Elliott
A new report ‘The role for nuclear within a low carbon energy system’ from the Energy Technologies Institute, claims that the UK could have 50GW of nuclear power plants by 2050, including Small Modular Reactors (SMRs). Although it says, due to basic economies of construction and operational scale, ‘large reactors are best suited for baseload electricity production’, it notes that, based on using existing sites, there is ‘an upper capacity limit in England and Wales to 2050 from site availability of around 35 GWe’, and it could be less (e.g. if CCS plants need some of the sites). However, there could be more room for small nuclear plants (under 300kW) on new sites, at least 21GW and in theory up to 63GW.
By Dave Elliott
In a post-Xmas pre-new year Scrooge-type austerity mood, I worry about the money we are wasting on energy. If you look at Sankey diagrams of energy flows from primary resources to final end use, you will see that for many countries around half the raw energy input is wasted in the conversion process, most of it being rejected into the atmosphere as heat, for example from steam-based fossil and nuclear generation systems.
By James Dacey in San Francisco.
Droves of delegates poured into the Moscone Center in San Francisco today for day one of AGU Fall 2015 – the largest Earth and space-science meeting in the world, with a whopping 24,000 delegates expected over the week. Having arrived from the UK on Saturday night, the jet-lag has kicked in with a vengeance today, so a couple of the conference coffees were definitely in order this morning. I’m just taking a break now after an interesting session about communicating climate change, and whether those researchers who don’t engage in the public debate are “failing humanity”.
The room was packed to the rafters, no doubt down to the profile of the speakers. First up was James Hansen, the former NASA scientist who has been outspoken in his criticism of the recent COP21 climate discussions, or at least the lack of concrete proposals to cut carbon emissions. Hansen restated his beef with the deal and argued that the only workable solution is for authorities to collect a carbon fee at source, such as charging domestic mines for the weight of carbon they sell. This, he believes, is the most effective way to make renewable energy and low-carbon options more viable. Not one to pull his punches, Hansen described US Energy Secretary Ernest Moniz’s idea that China will be able to curb much of its carbon missions using carbon capture and storage (CSS) technologies as “pure unadulterated bullshit”.
By James Dacey in Berkeley, US.
This weekend politicians at the COP21 summit in Paris signed a landmark legal agreement to keep global temperature rises at bay by curbing carbon emissions. The tricky next question of course is: how are we actually going to do this? In this short video, civil engineer Arpad Horvath of the University of California Berkeley explains that one of the aspects will be a fundamental rethink of our urban infrastructures. Horvath believes we need to move towards “smart cities” with smaller carbon footprints at all levels – from greener individual buildings, to more sustainable transport networks.
by Liz Kalaugher, Vienna
The world’s deserts are in many ways ideal for solar power; the sunshine is generally plentiful. But there’s at least one snag – dust. Installing mirrors for concentrating solar power or photovoltaic panels disturbs the desert surface and increases dust generation. Coatings of dust on photovoltaic panels can reduce their efficiency by 10-40%. As a result, operators often wash mirrors and panels regularly. This consumes a lot of water, perhaps as much as the equivalent of 100 mm of rain a year, in areas where it’s in short supply. And it’s left to flow down into the sand.
Sujith Ravi of Temple University, US, detailed in the Energy and Policy session at the European Geosciences Union meeting in Vienna this morning how this water could be more than enough to support the growth of desert plants like agave and aloe. And that agave could be turned into a biofuel, enabling the co-location of two types of renewable energy in one place. Since it’s a low-growing plant, the agave never shades out the panels – it even prefers to grow in the shade itself – and it’s a low-maintenance, high-yield crop that could even decrease the amount of dust formation in the first place.