Archive for the ‘Climate’ Category

Professor Jim Skea to deliver public lecture on mitigating climate change

Committee on Climate Change portraits - 24/9/08.

Professor Jim Skea. 

The Royal Society Te Apārangi is to host Scottish Professor Jim Skea, from the Intergovernmental Panel on Climate Change, for a free public lecture to ascertain what science is telling us about the actions we can collectively take to reduce the rate of climate change.

The society notes the country’s recent experience with record high temperatures and severe weather events causing flood and coastal damage.

Professor Skea will discuss whether situations like these clearly relate to the effects of global warming.

Moreover, following the announcement that the United States plan to cease their participation in the 2015 Paris Agreement, he will offer policy and practical guidance into how New Zealand and the rest of the world need to manage the responsibility of mitigating climate change.

Professor Skea is the Chair of Sustainable Energy at Imperial College London and Co-chair of the Intergovernmental Panel on Climate Change (IPCC) Working Group III, the branch of the IPCC that looks at the actions which can be taken to reduce the rate of climate change.

A meeting for the IPCC’s Special Report on Climate Change and Land, one of three Special Reports that the IPCC will publish in the next two years, is being held in Christchurch the week starting 26 March 2018.

A video recording of this lecture will be made available shortly after the event.

  • Climate change: stormy weather ahead
  • Wellington | Te Papa, Soundings Theatre
  • 6pm Wednesday 21 March.

You can register here.


Cape Town – or will the hydro-illogical circle make it the cape of good hope?

Cape town

Cape Town is grappling with a severe water shortage. 

Plant & Food principal scientist Brent Clothier has emailed colleagues on the drought in the Western Cape province of South Africa which began in 2015.

At the sharp end of this drought is Cape Town. Clothier says Wikipedia has “a nice up-to-date assessment of the crisis” here.

 Despite water saving measures, dam levels are predicted to decline to critically low levels, and the city has made plans for “Day Zero” on 4 June 2018[1], when municipal water supply will largely be shut off. If this happens, Cape Town will be the first major city to run out of water.[2]

The only good news is that Day Zero has been extended to June 4 from May 11.

The delay has been attributed to the continued decline in agricultural usage and Capetonians reducing their water usage, said deputy mayor Ian Neilson.

The week’s average daily production of all water sources at the time of the extension – February 13 – was at 526Ml/day, above the target of 450Ml.

“Team Cape Town, we are getting there. We now need to see how low we can go to ensure that we stretch our water supplies as far as possible into the winter months by reaching the 450 million litre per day collective consumption target which equates to 50 litres per person per day,” said Nielson.

Meanwhile, the national government has declared the drought affecting the southern and western areas of South Africa a national disaster.

Clothier reckons “Day Zero” is almost a certainty, because there’s unlikely to be any rains before June.

Even before “Day Zero”, the drought has had major impact because

“… in response to the water shortage, the agricultural sector reduced water consumption by 50 percent, contributing to the loss of 37,000 jobs in the sector nationally, and leading to an estimated 50,000 being pushed below the poverty line due to job losses and inflation due to increases in the price of food. By February 2018 the agricultural sector had incurred R14 billion (US$1.17 billion) in losses due to the water shortage.”

Clothier asks whether such an outcome could have been foreseen?

His email includes this graph of the reservoir water-storage capacity for Cape Town, showing the race-to-the-bottom down to “Day Zero”.

Day Zero

Clothier comments:

It highlights something about the human condition which just offers a ‘shoulder-shrug and a hope-for-the-best’ response in the face of climate change.

We could change our ways, and adapt to the new norms.

Here’s the reason why we don’t adapt.  It’s because we believe in the “hydro-illogical cycle”.  …



Clothier explains this is a contemporary ‘perversion’ of Leonardo da Vinci’s first iteration of the ‘hydrological cycle’! [Check out]


Drought classification is extended to the Grey and Buller districts

Agriculture and Rural Minister Damien O’Connor has added the Grey and Buller districts on the South Island’s West Coast to the medium-scale drought declared in the lower North Island last month. 

The extension of the drought classification means the local Rural Support Trust and other recovery organisations get a funding boost of up to $50,000 to help their local communities.

O’Connor declared 13 districts across Taranaki, Manawatu-Whanganui and Wellington were in drought conditions just before Christmas after an extremely dry start to the summer. 

“On the back of an extremely wet winter that left many farmers unable to grow pasture or crops for spring, the early and unusual dry start to summer turned West Coast pastures from swamp to concrete,” O’Connor said.

“It was agreed that while farmers needed to plan for the worst, there was hope that the forecast rainstorms could break the drought before central government assistance became necessary. However, the Grey and Buller districts now meet the criteria for a medium-scale event.”

O’Connor, who is also the local MP for West Coast-Tasman, had been closely monitoring the dry-weather conditions in the lead-up to declaring the medium-scale event and today said there’s a watching brief on neighbouring areas including Murchison, which have missed out on rain. 

The Ministry for Primary Industries classifies medium-scale events as those that impact farms and communities at a district or multi-district level.

Central government aid includes tax relief and income assistance. The ministry is reviewing its drought policy framework with a new policy expected to be in place by the middle of this year. 

US scientists develop new tool to predict climate change effects on crop yields

University of Illinois researchers are attempting to bridge two types of computational crop models to become more reliable predictors of crop production in the American Corn Belt.

One class of crop models is agronomy-based; the other is embedded in climate models or earth system models.

They are developed for different purposes and applied at different scales, says Kaiyu Guan, an environmental scientist and the principal investigator on the research.

“Because each has its own strengths and weaknesses, our simple idea is to combine the strengths of both types of models to make a new crop model with improved prediction performance.”

Guan and his research team implemented and evaluated a new maize growth model, represented as the CLM-APSIM model, by combining superior features in both Community Land Model (CLM) and Agricultural Production Systems sIMulator (APSIM).

“The original maize model in CLM only has three phenological stages, or life cycles. Some important developmental stages such as flowering are missing, making it impossible to apply some critical stresses, such as water stress or high temperature at these specific developmental stages,” says Bin Peng, a postdoctoral researcher in Guan’s lab and also the lead author.

“Our solution is incorporating the life cycle development scheme of APSIM, which has 12 stages, into the CLM model. Through this integration, stresses induced by high temperature, soil water and nitrogen deficits, can be taken into account in the new model.”

Peng says they chose CLM as the hosting framework to implement the new model because it is more process-based and can be coupled with climate models.

“This is important as the new tool can be used to investigate the two-way feedback between an agroecosystem and a climate system in our future studies.”

As well as replacing the original maize phenology model in CLM with that from the APSIM model, the researchers have made several other innovative improvements in the new model. A new carbon allocation scheme and a grain number simulation scheme were added, as well as a refinement to the original canopy structure scheme.

“The most alluring improvement is that our new model is closer to getting the right yield with the right mechanism,” says Guan.

“The original CLM model underestimates above-ground biomass but overestimates the harvest index of maize, leading to apparent right-yield simulation with the wrong mechanism. Our new model corrected this deficiency in the original CLM model.”

Peng says the phenology scheme of APSIM is quite generic.

“We can easily extend our new model to simulate the growth processes of other staple crops, such as soybeans and wheat. This is definitely in our plan and we are already working on it.

“All the work was conducted on Blue Waters, a powerful petascale supercomputer at the National Center for Supercomputing Applications (NCSA) on the University of Illinois campus,” says Peng. “We are currently working on parameter sensitivity analysis and Bayesian calibration of this new model and also on a high resolution regional simulation over the U.S. Corn Belt, all of which would not be possible without the precious computational resources provided by Blue Waters.”

The study, “Improving maize growth processes in the community land model: Implementation and evaluation,” is published (HERE) in Agricultural and Forest Meteorology.

New research finds plants release up to 30% more CO2 than previously thought

New research co-authored by a University of Canterbury scientist and academics from around the world suggests that plant respiration is a larger source of carbon emissions than previously thought. It warns that as the world warms, this may reduce the ability of Earth’s land surface to absorb emissions due to fossil fuel burning.

The findings, published in the journal Nature Communications this month was co-authored by Professor in Plant Physiological Ecology Matthew Turnbull, Head of UC’s School of Biological Sciences. They are based on the comprehensive GlobResp database, which comprises over 10,000 measurements of carbon dioxide plant respiration from many plant species and from across the globe.

Merging these data with existing computer models of global land carbon cycling shows plant respiration has been a potentially under-estimated source of carbon dioxide release to the atmosphere.

Across the world, carbon release by plant respiration may be around 30% higher than previously predicted. As mean global temperature increases, the researchers estimate that respiration will increase significantly.

Such increases may lower the future ability of global vegetation to offset carbon dioxide emissions caused by burning of fossil fuels.

People understand that plants take up carbon dioxide in photosynthesis, but less well known is that they also release it by respiration, Professor Turnbull says.

“In this international collaboration, including measurements in New Zealand forests, we find that respiration losses of carbon dioxide by plant respiration is 30% higher than previous estimates, and is expected to increase more than expected under global warming. This could have a major impact on the net amount of carbon dioxide that remains in the atmosphere, which we know is a major driver of the greenhouse effect.”

Plants both capture carbon dioxide and then release it by respiration. Changes to either of these processes in response to climate change have profound implications for how much ecosystems soak up carbon dioxide emissions from burning fossil fuels.

The lead author, Professor Chris Huntingford of the UK Centre for Ecology & Hydrology says for too long, plant respiration losses of carbon dioxide to the atmosphere have been “the Cinderella of ecosystem computer modelling”, with carbon dioxide gains via photosynthesis stealing the attention.

The new research addresses this, using extensive measurements of respiration to guide computer-based calculations of how carbon cycles through trees and plants.

This study has been the result of an especially close collaboration over several years between field scientists, those who build computer models of how the global land surface operates, and researchers assessing expected future climate change.

The study uses plant respiration data from over 100 remote sites around the world, from hot deserts in Australia, to the deciduous and boreal forests of North America and Europe, the arctic tundra in Alaska, and the tropical forests of South America, Asia, Africa and northern Australia.

Paper details: Huntingford, C., Atkin, O.K., Martinez-de la Torre, A., Mercado, L.M., Heskel, M.A., Harper, A.B., Bloomfield, K.J., O’Sullivan, O.S., Reich, P.B., Wythers, K.R., Butler, E.E., Chen, M., Griffin, K.L., Meir, P., Tjoelker, M.G., Turnbull, M.H., Sitch, S., Wiltshire, A. and Malhi, Y. (2017) “Implications of improved representations of plant respiration in a changing climate.”

Nature Communications. DOI:


New method of assessing carbon footprints could identify “green” cattle

Implications of livestock farming on climate change should not be drawn from aggregate statistics, according to a study based on a new method of carbon footprinting for pasture-based cattle production systems that can assess the impacts of individual animals.

The new method, developed by a team from the University of Bristol and Rothamsted Research, records the environmental impact of each animal separately before calculating the overall burden of a farm.

Existing methods of carbon footprinting are primarily designed to quantify total greenhouse gas (GHG) emissions of a particular farm. They are unable to provide information on environmental performances of specific animals.

The ability to identify “green” cattle within a herd — cattle that produce lower emissions per kilogram of liveweight gain — promises more sustainable farming, they report in the study just published in the Journal of Cleaner Production.

The team applied both the new and old methods to field data collected at the North Wyke Farm Platform (NWFP), a Rothamsted state-of-the-art facility that supports three experimental farms over 63 hectares in Devon.

They demonstrated that the latter approach consistently underestimates levels of GHG emissions because it fails to consider sufficiently the impacts of poorly performing animals, which are known to produce disproportionally large amounts of methane through enteric fermentation.

“The research offers two important lessons that may seem paradoxical at first sight,” says Dr Taro Takahashi, Research Scientist at North Wyke and Senior Lecturer in Sustainable Livestock Systems and Food Security at Bristol Veterinary School, who led the research.

“Short-term, many carbon footprint estimates currently available are probably too low, which is clearly bad news for the industry. But long-term, this also means that mitigation of greenhouse gas emissions originating from ruminants could be easier than traditionally thought — if we are able to select the right animals through the right screening methods. And this is precisely what we are trying to achieve at North Wyke.”

The work also marked the first comprehensive evaluation of the three production systems at North Wyke.

“This study demonstrates the true value of primary data being collected by the NWFP team every day,” says Paul Harris, the facility’s project leader. “They can challenge our intuition and enhance our understanding of how we can make agriculture more sustainable.”

The new study comes as the debate about the role of livestock in sustainable global food production intensifies. In a report published this month, the Food Climate Research Network (FCRN) reiterated that livestock production is a net contributor to global warming regardless of the species and the rearing method.

“We agree with the FCRN report that ruminants cannot reverse climate change, even if they are grass-fed,” says Michael Lee, Head of North Wyke and Professor of Sustainable Livestock Systems at Bristol Veterinary School.

“However, as we discussed in our 2014 article in Nature, pasture-based livestock production systems have a multifaceted role in society — the point acknowledged, but not actively addressed, by the FCRN report.

“At Rothamsted, not only do we aim to advance knowledge on how to minimise negative impacts of agricultural production, as exemplified by the current paper, but also on how to optimise the positive contribution grazing livestock can bring to us as part of a well-designed food supply chain.”

Lee adds that such aspects include effective use of land unsuitable for growing crops, production of higher quality protein and more bioavailable micronutrients, improved animal welfare, prosperous rural communities and flood prevention. They all make up the bigger picture when looking for a sustainable future of food production.

Hayward kiwifruit in Bay of Plenty at risk from climate change

The most commonly grown variety of kiwifruit around Te Puke will not be commercially viable in the area by the end of the century, scientists predict.

A study into how climate change will affect production of the Hayward cultivar in the Bay of Plenty – the common bright green kiwifruit – has just been published in the New Zealand Journal of Crop and Horticultural Science.

The lead author, NIWA scientist Dr Andrew Tait,says it is globally recognised that the effects of climate change is an emerging risk to the economic value of fruit crops, especially those grown in warm, temperate regions such as kiwifruit.

“Our study shows that kiwifruit production around Te Puke steadily decreases over coming decades. It will be marginal by 2050 and most likely not viable by 2100 under all but the most stringent of global greenhouse gas emission options.”

The good news is that other parts of New Zealand will become suitable for kiwifruit production as temperatures rise.

About 90 per cent of New Zealand’s kiwifruit industry is based in the Bay of Plenty and more than half of that around Te Puke. Production is mostly the Hayward variety which is suited to the climate and soils of the area, including warm springs, mild summers and autumns and high sunshine hours.

Kiwifruit need sufficient “winter chilling” between May and July to produce high flower numbers in spring that result in fruit. High winter chilling, or colder sustained temperatures over this period, generally results in more flowers and an earlier flowering period.

Productivity significantly increased between 1980 and 2010 due to technology changes and the introduction of a chemical sprayed on the vines in late winter to improve the effects of winter chilling. New Zealand kiwifruit exports were worth $1558 million in the year ending June 2016 – up from $930 million the previous year.

But the use of the chemical, hydrogen cyanamide, may be restricted or banned in future.

“As air temperatures in New Zealand continue to rise, the potential for more years with marginal or poor winter chilling conditions steadily increases. This could put significant stress on the kiwifruit industry in the Te Puke area, particularly if hydrogen cyanamide is banned,” Dr Tait says.

“If this happens soon then there is an urgent need to consider the viability of Hayward kiwifruit production in other areas of the country, alongside genetic improvement.”

NIWA temperature data and high resolution mapping abilities showed areas further inland in the Bay of Plenty as well as Canterbury and Central Otago had potential as Hayward kiwifruit growing regions.

Through good planning, the New Zealand kiwifruit industry is likely to remain viable for many decades to come, Dr Tait says.