Historical Documents Reveal Arctic Sea Ice Is Disappearing At Record Speed

The Guardian - Dana Nuccitelli

Summer Arctic sea ice is at its lowest since records began over 125 years ago

The 2015 Arctic sea ice summertime minimum (699,000 square miles below the 1981-2010 average) is seen in a NASA visual representation of satellite data. Photograph: NASA/REUTERS

Scientists have pieced together historical records to reconstruct Arctic sea ice extent over the past 125 years. The results are shown in the figure below. The red line, showing the extent at the end of the summer melt season, is the most critical:

Time series of Arctic sea ice extent, 1850-2013, for March (blue line) and September (red line). Illustration: Walsh et al. (2016)

Arctic sea ice extent in recent years is by far the lowest it’s been, with about half of the historical coverage gone, and the decline the fastest it’s been in recorded history. Florence Fetterer, principal investigator at the National Snow and Ice Data Center, described the data reconstruction process in a guest post at Carbon Brief:

Prof John Walsh, now at the University of Alaska Fairbanks, and Dr Mick Kelly, from the University of East Anglia (now retired), were pioneers at retrieving data. They hand-digitised information from sources, such as aerial surveys, from the US Navy and UK Meteorological Office, and from the Danish Meteorological Institute’s yearbook maps (see examples from 1978 and 1979 – both pdfs).
Walsh, along with Prof William Chapman from University of Illinois, used these various sources to make monthly grids in Arctic and Southern Ocean sea ice concentrations, covering the period 1901-95.

However, as Fetterer explains, gaps remained in their records, which have now been filled into the NSIDC dataset using a variety of sources:

• The sea ice edge positions in the North Atlantic, between 1850 and 1978, derived from various sources, including newspapers, ship observations, aircraft observations, diaries and more. 
• Sea ice concentration data from regular aerial surveys of ice in the eastern Arctic by the Arctic and Antarctic Research Institute, St. Petersburg, Russia, beginning in 1933. 
• Sea ice edge positions for Newfoundland and the Canadian Maritime Region from observations, for 1870 to 1962. 
• Detailed charts of ice in the waters around Alaska for 1954 to 1978, originally the property of a consulting firm (the Dehn collection). 
• Arctic-wide maps of ice cover from the Danish Meteorological Institute from 1901 to 1956. 
• Whaling ship logbook entries that noted ship position along with an indication of whether the ship was in the presence of ice.

A Danish Meteorological Institute ice chart for August, 1926. The red symbols mark the location of observations recorded in ship logbooks. Illustration: Walsh et al. (2016).

It’s not just the area of ice-covered ocean that’s shrunk; in fact, the volume of Arctic sea ice has declined even faster. As illustrated in this video created by Andy Lee Robinson, about two-thirds of the summer sea ice has disappeared in just 36 years as the warming oceans have thinned the ice.

Annual minimum Arctic sea ice volume 1979–2015, created by Andy Lee Robinson. 

Previous research has also shown that Arctic sea ice is at its lowest level in at least 1,450 years, and the recent decline is mostly due to human-caused global warming.
This dramatic change may be causing ripple effects throughout the Earth’s climate system. For example, some research has suggested a possible connection between the Arctic sea ice decline and the intensity of California’s recent record drought (although the connection is not definitive). Those record drought conditions in turn contributed to the intense wildfires currently raging across California. Other research has suggested possible connections between disappearing Arctic sea ice and extreme weather events, but again, these connections aren’t yet definitive.
The loss of ice causes what scientists call a feedback effect. Ice is highly reflective, while the ocean beneath is dark. When the ice on the ocean surface melts, the Arctic becomes less reflective and absorbs more sunlight, causing it to warm faster, melting more ice, causing more warming, and so on. This feedback is one of the main reasons why the Arctic is Earth’s fastest-warming region, with temperatures rising about twice as fast as in lower latitudes.
Swedish scientist Svante Arrhenius predicted this Arctic amplification effect in 1896. As a result, the Arctic is effectively the ‘canary in the coal mine’ of the Earth’s climate, showing us the dramatic effects human-caused global warming can have on the climate system. The signal is clear, but the question remains whether we’ll take action, or stay in the coal mine.

Links

• Climate urgency: we've locked in more global warming than people realize
• Climate scientists make a bold prediction about sea level rise
• Rejection of experts spreads from Brexit to climate change with 'Clexit'
• New research shows penguins will suffer in a warming world

Climate Change Will Create New Ecosystems, So Let’s Help Plants Move

The Conversation - Ary Hoffmann

Australia's treeless alps are vulnerable to the spread of woody shrubs. Alps image from www.shutterstock.com

Australia's ecosystems are already showing the signs of climate change, from the recent death of mangrove forests in northern Australia, to the decline in birds in eastern Australia, to the inability of mountain ash forests to recover from frequent fires. The frequency and size of these changes will only continue to increase in the next few years.
This poses a major challenge for our national parks and reserves. For the past 200 years the emphasis in reserves has been on protection.
But protection is impossible when the environment is massively changing. Adaptation then becomes more important. If we are to help wildlife and ecosystems survive in the future, we'll have to rethink our parks and reserves.

A weedier world
Climate change is predicted to have a substantial effect on our plants and animals, changing the distribution and population of species. Some areas will become unfavourable to their current inhabitants, allowing other, often weedy, species to expand. There will likely be widespread losses in some ecosystems as extreme climate events take their toll, either directly by killing plants and animals, or indirectly by changing fire regimes.
While we can model some of these changes, we don't know exactly how ecosystems will respond to climate change.
Australia has an extensive natural reserve system, and models suggest that much of this system is expected to be altered radically in the next few decades, resulting in the formation of totally new ecosystems and/or shifts in ecosystems.
Yet with rapid climate change, it is likely that ecosystems will fail to keep up. Seeds are the only way for plants to move, and seeds can only travel so far. The distribution of plants might only shift by a few metres a year, whereas the velocity of climate change is expected to be much faster.
As a result, our ecosystems are likely to become dominated by a low diversity of native and exotic invasive species. These weedy species can spread long distances and take advantage of vacant spaces. Yet the exact nature of changes is unknown, particularly where evolutionary changes and physiological adaptation will assist some species but fail others.
Conservation managers are concerned because with increasing weediness will come a loss of biodiversity as well as declines in the overall health of ecosystems. Plant cover will decrease, triggering erosion in catchments that provide our water reservoirs. Rare animal species will be lost because a loss of plant cover makes them more susceptible to predators. A cascade of changes is likely.

From conservation to adaptation
While climate change threats are acknowledged in reports, we continue to focus on conserving the state of our natural environments, devoting scarce resources to keeping out weedy species, viewing vegetation communities as static, and using offsets to protect these static communities.
One way of preparing for the future is to start the process of deliberately moving species (and their genes) around the landscape in a careful and contained manner, accepting that rapid climate change will prevent this process from occurring quickly enough without some intervention.
Overseas plots covering several hectares have already been established that aim to achieve this at a large scale. For instance, in western North America there is a plot network that covers 48 sites and focuses on 15 tree species planted across a three-year period that covers temperature variation of 3-4°C.
In Australia, a small section of our reserve system, preferably areas that have already been damaged and/or disturbed, could be set aside for such an approach. As long as these plots are set up at a sufficiently large scale, they can act as nursery stock for the future. As fire frequency increases and exceeds some plants' survival capabilities, the surviving genes and species in these plots would then serve as sources for future generations. This approach is particularly important for species that set seed rarely.
Our best guesses about what will flourish in an area in the future will be wrong in some cases, right in others, but ongoing evolution by natural selection in the plots will help to sort out what really can survive at a particular location and contribute to biodiversity. With a network of plots established across a range of natural communities, our protected areas will become more adaptable for a future where many species and communities (along with the benefits they provide) could otherwise be lost entirely.
As in the case of North America, it would be good to see plots set up along environmental gradients. These might include from wet to dry heading inland, and from cold to warm heading north-south or with changing altitude.
One place to start might be the Australian Alps. We could set aside an area at higher altitude and plant low-altitude grasses and herbs. These may help current plants compete against woody shrubs that are expected to move towards our mountain summits.
Lower down, we might plant more fire-tolerant species in mountain ash forests. Near the coast, we might plant species from further inland that are better at handling drier conditions.
The overall plot network should be seen as part of our national research infrastructure for biodiversity management. In this way, we can build a valuable resource for the future that can serve the general community and complement our current ecosystem monitoring efforts.

Links

• Are national parks the best way to conserve nature?
• Climate change will transform the bush … and we'll have to think big to cope
• We can't save all wildlife, so conservation laws need to change
• Climate change is placing increasing pressure on Queensland's ecosystems

Dairy’s (Climate) Changing Future

University of Melbourne - Lauren Hull

The dairy industry is adaptive by nature, but farmers are likely to face a range of new challenges due to the ever-increasing impact of climate change
Twenty years from now, dairy farming will look and feel different.
By 2040, farmers will have to deal with warmer temperatures and more extreme weather events, while more variable rainfall will see seasons shift and feeding strategies altered.
Summers will extend well beyond the usual summer period and dry spells will last longer.
The forecast change has prompted a team of researchers at the University of Melbourne's Primary Industries Climate Challenges Centre and Dairy Australia to apply climate modelling to specific farms to analyse how key Australian dairy regions might perform in the future.

A cow being milked at the University of Melbourne's robotic dairy at the Dookie campus. Picture: University of Melbourne

And beyond the impacts of a changing climate, the first-of-its-kind study has also asked: how will Australian dairy farmers be producing milk in the future?
The answer? The major finding across each of the regions and climate scenarios studied is that there is no one-size-fits-all approach to dairy farming under future climates.
Using three farms; in Victoria's Gippsland region, South Australia's Fleurieu Peninsula and north-west Tasmania, researchers applied climate, biophysical and economic models to develop projections for each farm system.
Researchers Dr Brendan Cullen and Dr Margaret Ayre, from the University of Melbourne, worked alongside scientists from the Tasmanian Institute of Agriculture, economists, farm consultants and farmers from the three regions to develop a comprehensive picture of how each farm might perform.
"Most significantly, we'll see a shift in the pasture growing season. Growth rates will be higher in winter and early spring but lower for the rest of the year. Overall, this means less pasture production and that will create a real feed challenge. Farmers will need to adapt. They might buy in more feed, or alter stocking rates and calving times."
The climate change scenarios for 2040 were based on the climate projections used in the IPCC 5th Assessment report. The team also used a biophysical dairy modelling tool co-developed at the University of Melbourne ('DairyMod') to assess the impacts of the future climates on dairy production systems.
Dr Cullen says the 2040 timeframe was chosen because it provided projections that were tangible for farmers involved in the project.
"The farmers we were working with wanted to know what their system would look like one generation into the future," Dr Cullen says.
"They felt that there was too much uncertainty beyond 2040 about how farm systems would change, particularly through genetic and technological advances, along with uncertainty about climate change projections."

A video summary of the project's findings. Video: Dairy Australia

Three regional working groups, each made up of five or six farmers and farm consultants, helped the research team identify a representative farm in each region on which to base the projections. While every farm is different, Dr Cullen says this approach enabled them to test a diverse range of production systems in detail and apply some of the lessons across the regions.
The working groups were involved in the project from inception to completion, playing a vital role in both ensuring the research questions were locally relevant and 'ground-truthing' the results, he explained.

Development options
Dr Cullen and the team looked at a range of different business development options to explore how farmers might adapt their farms to manage challenges such as this. The options broadly represented a trajectory from 'less intensified' to 'more intensified' dairy production.
One critical finding was that climate change had a negative effect on the profitability of each farm regardless of the development option, largely because higher temperatures and longer dry spells reduced pasture utilisation.
Across the three case study farms, the research identified a loss of operating profit of 10-30% due to climate change in 2040 if farmers did not adapt to the warmer and drier climates.
But each development option offered opportunities and trade-offs, depending on the region and farmers' attitudes to risk. For example, large profits could be made in the more intensified systems when milk prices are high and feed is relatively cheap, but large losses are likely if milk price is low and feed is expensive. The least intensified options generally had the lowest average profit, but also had the least year-to-year variability in profit and were generally less impacted by climate change.

Despite climate change impacts, other factors are more critical to dairy farm profitability, including milk prices. Picture: mojitopt/Flickr

Importantly though, milk price is expected to affect profitability more than climate change, with the current milk price crisis serving to highlight the importance of milk price variability in dairy businesses.
According to Dr Cullen, if the milk price variation that has been observed over the last decade were to continue, it will have a greater influence on farm profit than the direct impacts of climate.
The Australian dairy industry has been on a long term trend of intensification, but Dr Cullen says the simpler, less intensified systems tested are realistic alternatives under future climates.
"For dryland dairy farms, we found a less-intensified system had similar average levels of profitability but were less risky compared to more intensive systems," Dr Cullen says.
"That might mean a shift to smaller herds, less grain feeding, more off-farm agistment or lower stocking rate – the reverse of what we've seen in past decades.
"Dairy farming can certainly continue to be viable into the future, but the project has clearly identified that there is a need for the industry and farmers to continue to adapt to changing climatic conditions in order to remain profitable."
For project leader Gillian Hayman, a dairy extension consultant at Dairy Australia and dairy farmer from southern Gippsland, the project's findings have confirmed the challenges she sees ahead for the dairy industry.
"Many of the farmers involved in the research had observed and managed through variable climatic seasons in the past. Floods, bush fires, heat waves, extremely wet winters and extended dry periods have all been a part of the last 15 years for farmers," she says.
"Dairy farmers already need to be at the top of their game, adapt to conditions and continually review their game plan from season to season. Climate change is yet another pressure on farmers along with milk price variability."
Good management and skill development has been critical in the past and will continue to be crucial, to ensure dairy farmers can manage profitable businesses into the future, Ms Hayman explained.
Dr Ayre led the social science component of the project, interviewing farmers and farm consultants to gauge the level of preparedness for climate change.
"We found that dairy farmers have a good awareness of what climate change will mean for their system, and that they're generally confident that they can adapt to incremental changes – for example, by adjusting feeding regimes and calving patterns,'' Dr Ayre says.

Dr Brendan Cullen (second from right) and Dr Margaret Ayre (far right) chat with farmers in Gippsland during a workshop. Picture: Gillian Hayman

"One area that we're concerned farmers aren't prepared for is the more extreme changes from climate averages. Recent heat waves have been a challenge for many."
Dr Ayre and the team said one of the strengths of the industry was the opportunity for professional development through discussion workshops, much like those conducted through their project.
Farmers reported that learning from peers was key when adopting new management practices.
The project suggests the dairy industry can support adaptation by farmers by providing specific professional development in business risk management including financial risks (seasonal and annual budgeting), biophysical risks (farm water planning) and social risks (farm workforce planning). A strong advisory sector is also critical to supporting adaptation and the dairy industry can support this through playing a role in coordination and linking private advisors, industry and government extension services with farmers and their networks.
Positively, the research team found that dairy farmers are already adapting to the changing climate conditions.
Farmers reported they were increasing the amount of shade and shelter available for stock during extreme weather events, increasing farm water storage and carrying larger fodder reserves from year to year.
The study's predictions on what future climates will mean for pasture production and farm profitability highlight the critical need for the industry to foster continued and more widespread adaptation in a warming and drying climate.

Featured academics: Dr Brendan Cullen | Dr Margaret Ayre

Links

• Climate change: what it means for fruits
• The black spot on Australia's chilli industry