Report provides insights into growing food under challenging dry conditions

Long-term planning for increasingly severe and frequent drought is needed now by industry bodies, regional councils and government, to reduce the strain on farmers and growers over the next decades, a new report highlights.

Commissioned by three National Science Challenges, the report Growing Kai Under Increasing Dry brings together insights from farmers, growers, industry bodies, researchers and government about how to adapt to intensifying drought conditions.

These insights were garnered in a series of online webinars and a one-day symposium in May, hosted by Deep South, Resilience to Nature’s Challenges, and Our Land and Water National Science Challenges.

A national long-term climate change adaptation strategy that supports farmer resilience is needed to reduce the economic risks of increasing drought, says Nick Cradock-Henry, a Manaaki Whenua – Landcare Research senior researcher who presented at the events. Continue reading

NZ’s warmest June on record – why climate change research is regarded as critical

The June Climate Summary was published today, showing last month was the warmest June on record for the country.

The average temperature was 2.0°C above average, the 13th time this has happened since 1909.

Several records were broken with 24 locations having their warmest June on record.

The highest temperature was 22°C at Hastings on June 26 and Leigh on June 19.

Taranaki is still leading the sunniest location table.

The data were being posted at much the same time as AgResearch Research Director Trevor Stuthridge was describing the recently released advice of the Climate Change Commission as an endorsement of the research being done to support agriculture’s shift to lower emissions.

The Climate Change Commission was established to provide advice to the Government about the paths to meeting New Zealand’s climate change targets. Continue reading

Climate scientists are making shift to a new “normal”

NIWA climate scientists are redefining what’s normal when it comes to the weather.

A team of technicians and researchers are embarking on a major project to update New Zealand’s “Climate Normals” that will take at least six months to complete.

Climate Normals are what scientists define as an average statistic based on a 30-year timespan. So when climatologists describe rainfall amounts as “above normal” or temperatures as “below normal”, they are currently comparing the figures to a 30-year average of data collected between 1981 and 2010.

Climate Normals are important because they act as a benchmark against which recent or current weather observations can be compared and are also widely used as a representation of the most likely climate conditions for a given location and time of year.

But soon “normal” will shift to the new 30-year timespan between 1991 and 2020. The change has been prompted by the World Meteorological Organization (WMO) which determines the 30-year period as the accepted statistical convention. Updating to the new 30-year time period is a requirement for all WMO member countries around the globe.

The switch won’t change any actual weather measurements, but due to our warming planet, it will mean the new temperature normal will be higher than previously.

Technological advances have also been huge in the past 30 years which has meant changes to the way data are collected.

Principal climate technician Andrew Harper says his team continually undertake field verifications of the data they are collecting and calibrate the instruments.

“This is especially important because there has been a proliferation of different types of weather stations in recent times and we need to ensure that they each measuring the variables the same way.”

Climate scientist Raghav Srinivasan says the process of changing the normal takes several steps. After site checks data must be quality controlled, audited and standardised.

One of the crucial steps is identifying and then filling gaps in the data. Gaps can be caused by a range of issues from severe weather damaging the weather station, transmitting malfunctions and something as simple as a spider web affecting the size of a hole through which rain passes into a measuring container. Filling the gaps can be done using a range of calculations partly derived from data of nearby stations.

“Even if there is a complete 30-year record we need to make sure it is good quality so we follow several processes, including auditing selected variables,” Srinivasan says.

It is a detailed and painstaking process that he likens to good housekeeping.

“It’s a chance to look back and check the data and go into the details and it’s going to take quite a few of us to achieve.

“Tracking changes over time is fundamental to climate science.”

It is expected the new Climate Normals will be ready at the end of the year.

Source:  NIWA

NZ scientist to head project to detect methane in global satellite mission

Dr Sara Mikaloff-Fletcher, an atmosphere and ocean scientist at Niwa, has been appointed the scientific leader of a New Zealand-led $6 million project to find and reduce farming emissions

New Zealand will become the testing ground for an international space mission to detect, by satellite, methane emissions from animals’ stomachs anywhere in the world.

The 350kg satellite will have its mission control based in New Zealand after the Government contributed $26m to the mission. The location of the ground control centre in New Zealand is still to be announced.

It will be launched in 2022 and will be capable of focusing on swathes of farmland anywhere in the world, revealing how much methane is being released at higher resolutions than before. Continue reading

Pollution levels (nitrogen oxide) soar in level 3 – carbon dioxide levels are bad news, too, despite boost for plant growth

Traffic pollution measurements in Auckland have soared to levels higher than those before lockdown since Level 4 restrictions were eased on Tuesday, NIWA air quality scientists say.

Meanwhile another set of scientists was addressing another climate change issue regarding the relationship between carbon dioxide levels and carbon dioxide.

NIWA’s analysis of nitrogen oxide levels, mostly caused by road traffic exhaust, shows levels in the past three days have far exceeded those leading up to March 26 when the country was effectively closed.

NIWA air quality scientist Dr Ian Longley says levels yesterday and today, recorded at morning rush hour, are partly due to very light winds which have amplified the effect.

Today’s level at Takapuna was 250 mg/m which has not been as high since August last year.

“I was surprised to see the levels shoot up so high so quickly but it is likely they will return to pre-lockdown levels fairly quickly,” Dr  Longley said. Continue reading

Things are hotting up – NIWA report is rich with data, if you want to talk about the weather

NIWA data  show the global trend of warming weather continued in 2019, setting record average temperatures in many parts of the country

It was New Zealand’s fourth warmest year since 1909 (when records began) with an average temperature of 13.37°C.

NIWA’s annual climate summary shows New Zealand has not had a month with below-average temperatures for 35 months.

Five of the past seven years have been among New Zealand’s hottest on record.

Data from Australia’s Bureau of Meteorology show 2019 was Australia’s hottest and driest year.

The hottest year on record for New Zealand was 2016, when an average nation-wide temperature of 13.45°C was recorded. The years 1998 and 2018 are tied in second place with an average of 13.41°C.

Annual temperatures were +0.5 to +1.2 degrees Celsius above the annual average across the majority of New Zealand.

Yearly rainfall in 2019 was above average in western Southland and parts of Westland, but large areas of the country – including Northland, Auckland, the Bay of Plenty and parts of Waikato, Hawke’s Bay, the Wairarapa and Marlborough – had only 50–80 per cent of their usual rainfall.

The Science Media Centre asked experts to comment on the NIWA summary. Continue reading

New reports highlight the flood risk under climate change

Two reports from NIWA and the Deep South National Science Challenge reveal new information about how many New Zealanders, how many buildings and how much infrastructure could be affected by extreme river and coastal flooding from storms and sea-level rise.

One report looks at what would happen when rivers are flooded by heavy rain and storms, while the other examines flooding exposure in coastal and harbour areas and how that might change with sea-level rise.

NIWA researcher Ryan Paulik says the New Zealand Fluvial (river) and Pluvial (rainfall) Flood Exposure report is a first cut at identifying the amount of exposure to flooding at a national scale based on available flood maps.

Their findings show that across the country almost 700,000 people and 411,516 buildings worth $135 billion are presently exposed to river flooding in the event of extreme weather events. Continue reading

International weather and climate experts gather in Wellington

Weather and climate experts from around the world are meeting in Wellington this  week to discuss the successes of a global scientific model focused on improving the accuracy and reliability of weather and climate forecasting.

The National Institute of Water and Atmospheric Research (NIWA) will host the meeting at Te Papa tomorrow where delegates will renew their membership in the global Unified Model Partnership – one of the world’s foremost weather and climate forecasting research collaborations.

In its global form the Unified Model can provide information on weather systems around the world and the links between then. Regionally it can provide information on detailed weather and climate impacts at the kilometre scale using world-leading forecasting technology. Continue reading

Paper which challenged NZ temperature records gets its rebuttal

The credibility of New Zealand’s long-term temperature records is the subject of a new post at Sciblogs (HERE) by Gareth Renowden, a member of the committee of the NZ Meteorological Society.

recalls that back in the spring of 2014, a paper was published based on the authors’ recalculation of the country’s  long-term temperature record.

This work  was based on calculations made to support their court case against the National Institute of Water and Atmospheric Research (NIWA), which they emphatically lost.

It contended New Zealand’s long-term warming rate was only a third of the amount previously calculated.

Gareth Renowden now writes:

As I pointed out at the time, it was riddled with errors and bad scholarship, but it appeared in the peer-reviewed literature, and so required a peer-reviewed rebuttal.

It’s taken a while, but in the last few days Comment on “A Reanalysis of Long-Term Surface Air Temperature Trends in New Zealand” has been published in Environmental Modelling and Assessment3.

Led by NIWA principal climate scientist Brett Mullan, the authors are Jim Salinger, who first established the NZ long term temperature record4, Professor Jim Renwick from VUW, and David Wratt, now Emeritus Scientist (Climate), at NIWA, and an Adjunct Professor in the New Zealand Climate Change Research Institute at VUW. You could fairly describe them as experts – and their “comment” might better be called a demolition.

Here’s their conclusion:

In this paper, we identify what we consider to be several methodological flaws in the [de Freitas et al] paper. We conclude that, as a consequence, the temperature trend of an increase of 0.28 °C per century for the period 1909–2009 for New Zealand land surface temperatures derived in the dFDB paper is substantially too low, and that no need has been established for significant downward revision of the trend of around 0.9 °C per century found in previous studies.

They then provide a handy summary of the main flaws – which I’ve paraphrased below:

  • dFDB claimed their paper was the first to properly use a methodology developed by Jim Salinger and Rhoades, first published in 1993. It wasn’t – in two senses. It wasn’t the first, and they didn’t use it properly.
  • dFDB claimed NIWA’s long term temp record was based on calculations from Jim Salinger’s PhD thesis. It wasn’t.
  • dFDB’s interpretation of the Rhoades and Salinger technique was mistaken and flawed, using station overlaps that were too short and ignoring changes in maximum and minimum temperatures. The result was that they failed to make many adjustments that were required, and therefore underestimated the actual warming.
  • dFDB made a few arithmetical errors, dealt with missing data incorrectly, and mishandled trends in the Auckland and Wellington series.
  • dFDB ignored other lines of evidence that support warming of 0.7-1.0°C per century, such as temperature series derived by the Berkeley Earth project, the decline in NZ’s glaciers, and analyses of sea surface temperatures around NZ.

In conclusion, Gareth Renowden  (MA Oxon) says the full paper is “an elegant and polite deconstruction of a shoddy, politically motivated piece of work that should never have passed peer review first time round”.

New Zealand river water quality trends show cause for optimism

River water quality around New Zealand has improved significantly in the past decade, according to the latest National River Water Quality Trends (2007-2016) data released this week by Land, Air, Water Aotearoa.

For all river water quality parameters monitored over a 10 year period, more sites were improving than deteriorating.

This encouraging national picture has been welcomed by scientists and local government who say freshwater ecosystem management practices as likely contributing to the progress.

The data, recording the results from regular water quality monitoring carried out over the past 10 years, show the majority of the country’s rivers rate positively.

The information relates to nearly 1500 freshwater sites that are regularly monitored for water quality by regional or unitary councils.

Data are supplemented by the National Institute of Water and Atmospheric Research.

Trends analysis was led by Cawthron Institute Freshwater Group Manager and Ecologist, Dr Roger Young.

He described the overall picture as encouraging and said:

“Looking back from 2016 at a decade of data, for every monitored parameter, more sites showed evidence of improving water quality, than degrading.

“My hope is this could represent a turning point in New Zealand’s river health story.

“While this analysis gives us cause for optimism, water quality is just one indicator of river health and there is still more work to be done. While all parameters show there are more sites improving than degrading, there are still degrading sites for all parameters.

“In order to continue further improvements, we need to invest in freshwater ecosystem management, routine monitoring, and further research and innovation.”

The National River Water Quality Trends (2007\ – 2016) released by LAWA follows a similar 10 year analysis released in 2015 by National Institute of Water & Atmospheric Research (NIWA).

Compared with the 2015 report, a change in the trend of nitrogen is particularly noteworthy, with significant progress in the number of improving sites compared with the number that are deteriorating.

The trends are based on analysis of the comprehensive data that’s freely available on the LAWA website. Regular water quality monitoring by New Zealand’s Regional and Unitary Councils, supplemented with NIWA data, means there’s water quality info for nearly 1,500 sites.


The LAWA website (HERE) provides more detailed information about the health of rivers in 16 regions around the country.

Source: Land Air Water Aotearoa