Expert opinion from University of Auckland - Waipapa Taumata Rau
The climate is changing because of human activities. It also varies naturally. How do we sort out what is going on and why and use the information for better planning for the future? Indeed, climate science is vital to New Zealand if the country is to have the information needed to adapt to climate change, but the necessary research and information is threatened.
I live in the Auckland area and experienced the January 27, 2023 rain bomb (we got 280 millimetres in one day in my area on the North Shore) – less than three weeks later came Cyclone Gabrielle. It was evident to me that NZ was insufficiently prepared for the increasing climate extremes with climate change. Globally, 2023 is the warmest year on record at about 1.4C above pre-industrial values.
But how much of an event such as Gabrielle is chance – random acts of weather – and how much is pre-determined by climate changes caused by humans?
There is always a lot of natural variability occurring with weather and interactions of the atmosphere with the oceans, land, and cryosphere. El Niño is a natural climate variation and is inherently a coupled ocean-atmosphere phenomenon: that is, the ocean and atmosphere working in tandem to cause fluctuations in the climate. El Niño is a warming of the tropical Pacific Ocean surface, so that there are above-average sea surface temperatures, while La Niña is a cooling of the same region with below-average temperatures. Both change the global atmospheric circulation, which influences patterns of weather systems and temperature and precipitation around the world.
As these phenomena set up, they help us predict (with some uncertainty) patterns of weather for up to a year in advance, but they are not predictable for longer times. Other facets of climate are predictable for much longer, especially human-induced climate change. Even so, all weather events are embedded in the changing environment, and consequently weather includes elements of both the random and pre-determined. Decision makers need to understand this and plan in ways that accommodate both.
On March 20 this year, Newsroom featured an article about how local councils are stumbling forward in planning for the future, making use of completely inappropriate projections of the future climate. These were not predictions but possible “what if” scenarios if humans continued to emit carbon dioxide and other pollutants into the atmosphere at various rates. As Newsroom reported, nine regional councils and eight district councils commissioned Niwa to prepare regional climate projections in the past few years. Some of those, like Auckland, are working those temperatures into their decision-making.
These scenarios, developed by the Intergovernmental Panel on Climate Change for planning purposes, represent possible emissions, as distinct from likely emissions. Many climate models have been used to make projections of future weather and all have uncertainties, as well as the uncertainties in the prescribed emissions that depend on unpredictable human behaviour. Which models are most credible (and useful) in the New Zealand context need to include assessments that are specific to our region.
In other words, if councils hope to plan for the future, they need access to long-term sound continuous research that is specific to New Zealand. Yet there is inadequate work in that area in New Zealand, including at Niwa. Too much climate research funding is episodic, not continuous. As a climate change scientist, I see the urgent need for sustained funding to improve research and proper assessments of the best estimates of what will likely happen in the future, including the extremes. Translating what we are adapting to into useful information for councils and decision makers of all kinds is a major research task and should not (and cannot) be done by councils alone.
How big is the human component?
The changing flows of energy through the climate system suggest that it is less than 0.5 percent of the natural flow of energy from the Sun that ultimately radiates back to space. The energy imbalance arises from the increases in carbon dioxide and other greenhouse gases in the atmosphere that change atmospheric composition and interfere with the natural flows and produce heating. However, the imbalance is very large compared with direct human heating from all sources and it accumulates.
The main memory of the accumulated energy imbalance is the oceans, which are warmer by nearly 1C, and the atmosphere above the oceans is warmer and moister as a result; the atmospheric water vapour over the oceans has increased by about 10 percent since the 1970s. As storms reach out about four times the radius of their precipitating area to grab moisture and bring it into the storm, it rains harder.
There is always a drought somewhere, and the main cause of where large-scale droughts occur is El Niño cycles. Water is the great air conditioner of the planet and if there is water on the surface of the land, extra heat will largely go into evaporation. But when the conditions on land are dry, the heat dries out soils and vegetation raising temperatures further, increasing risk of wildfire. In drought the effects accumulate.
Human-induced climate change occurs on long time scales: 20 years is a reasonable estimate for noticeable significant changes, which is when it becomes clear that there is an underlying new normal of a warmer moister environment that all weather events are exposed to. A warming climate exacerbates natural events (storms and droughts), leading to greater extremes. It is essential to track and understand the extremes and the integrated effects on plants, forests, fisheries, water resources, farming, and cities. It means discerning the causes of the anomalous conditions, and the roles of climate change (and thus likely to continue), El Niño, random weather systems, and how these interact with each other. If we can model these in a computer then scientists are in a position to make better forecasts on multiple time scales and translate this into useful information for decision makers of all kinds, including councils.
We don’t have that capability in New Zealand, and as I’ve argued in Nature magazine, developing it requires sustained funding and commitments to generating and developing products for dissemination. Climate change is a major long-term threat that requires not only mitigation and adaptation, but information!
Unfortunately we are currently governed by the wrong people.
There’s a big group of scientists working in and around climate change who, of course, agree with this piece. More importantly, despite large cuts slicing through climate research, on top of the usual funding having no increases with inflation, the community is coming together to express similar messages about the need to solve these problems with trusted information. We need new funding mechanism that can support the research communities that “track and understand the extremes and the integrated effects on plants, forests, fisheries, water resources, farming, and cities.” We need funding that supports these communities to build trust in solutions. Unfortunately the new Panel overseeing research funding has negligible climate change expertise, and is charged with shifting public-good research to commercial strategies that tend to erode the trust that forms the foundation of solutions to the major challenges of the 21st century.
I’m not so sure about that. The last “people” in Govt wanted to push ahead with a silly $13b Lake Onslow pump storage project without having done any analysis of the impact of future weather patterns that could be used to promote a sensible development of wind, hydro, solar, geothermal and batteries built as and where needed. I would have thought that its main promoter Dr Bardsley, as a professor of Hydrology, would have done the sort of work proposed by Dr Trenberth to define what is meant by “dry year” in the context of NZ power planning. Such forecasting would need to consider a long-term view of how climate change would impact NZ patterns of weather, to demonstrate how often we might expect a 6-month hiatus of a lack of sunshine, wind and hydro all at the same time. Indeed, this would have helped justify the dubious economics of requiring taxpayers to fund the cost of electrically pumping $3b of water uphill and then leaving it to sit there waiting for 20 years before the next drought.
Hi John – your comments on Lake Onslow are not really related to Kevin’s theme, but I’ll respond for information. First, a correction – Onslow scheme construction was estimated at $16b, not S13b. The $13b was with respect to the other dry year option identified by the NZ Battery team, comprising a multi-technology approach using biofuel and new reserve geothermal. The Onslow option was identified as being cheaper to run but more expensive to build. A detailed business case report was initiated by NZ Battery in 2023 to sort out the best option (or maybe some combination of two options). With the change of government the order was given that the report must not be completed. It will most likely be completed after the next change of government. The Onslow scheme may or may not proceed then.
Your reference to the need for knowledge of a simultaneous 6-month overlap probability of low solar / wind / hydro is incorrect. Wind and solar fluctuate at much shorter time scales than the multi-month periods that can happen with low inflows. When the hydro lakes are at their minimum, even a single a cold calm winter night will have a big impact. The more that we have new solar panels and new windfarms that are then not generating then, the greater the impact will be. There is no need at all to attempt a detailed complex analysis on uncertain climate change scenarios and probability overlaps. All we need to know is: the larger the energy storage we can get (by whatever means) the more robust our power system will be against whatever climate change will throw at us.
Finally, it is disappointing to see the tired old straw man tactic applied once again to the Onslow scheme. It would indeed be hard to imagine anything more stupid than pumping water up a hill to leave it to sit there doing nothing except evaporating, waiting for a dry year. I really don’t know why this strange idea has not gone away by now, or how it originated. Yes, Onslow construction is motivated for dry year support. But in operation it would be spending almost all of its time to support fluctuating wind and solar power – in fact, actually enabling a lot of new wind and solar by making them more economic through provision of an electricity floor price. There’s no much economic point in generating lots of power when the wind blows if the selling price falls to zero.
“Climate change is a major long-term threat that requires not only mitigation and adaptation, but information.”
While better and more information will always help toward forecasting future climatic conditions, we already know the broad trend. More CO2 in the atmosphere has created a warmer climate with associated climate changes.
I suspect that the greater need, rather than more information, is the need to effectively and urgently act to reduce GHG emissions and reshape our civilisation toward a truly sustainable state. Our existing Government believes (or pretends to believe) that the necessary changes toward a better climate future will be driven by market forces. A totally misguided belief, in my humble opinion.
I agree, and experience shows that the private sector will not solve this problem unless in their interests to do so. So government should provide incentives; government as such does not have to solve it by itself, but no-one else has the entire national interest as their purview.
The “broad trend” does not apply well to local spots and becomes very difficult to translate to various sectors of the economy; often requiring social scientist input. It is important to look at the whole, not just pieces or they can easily be at odds.
The comment about Lake Onslow was a bit glib. There are challenges in properly utilizing intermittent sources of electricity (wind and solar) and how not to just “spill” it: rather pumping water uphill as part of a “pumped hydro” scheme is very sound, but there must be many smaller more sensible options that Lake Onslow (cf Switzerland). Pumped hydro is a very efficient “battery” in the long term. The exercise mentioned by John Irving requires a very good model of the climate run hundreds of times to generate sound statistics.
Pumped storage schemes are not more or less “sensible” based on their energy storage capacity. Different schemes do different things. Most pumped storage schemes around the world have small energy storage relative to generating capacity. They can buffer a constant-output nuclear power station through a daily demand cycle, for example. But that doesn’t preclude other schemes having large energy storage if there is also a need to buffer for a few months. Trying to build enough smaller schemes in New Zealand to add up to the 5 TWh storage capacity of Onslow would never work in terms of both construction economics and cultural / environmental impact – as the NZ Battery team found out when they attempted the exercise.
I’ve always been puzzled by the Lake Onslow proposal, and I’m even more puzzled by having it come up here. We need to understand the problem, and then address it. In the case of Lake Oslow it seem obvious more smaller schemes combined with renewable generation is far better. Lake Onslow is an example of the silver bullet approach, when solving climate change clearly requires silver buckshot. We need many well-targeted bright ideas, but we can’t allow them to blow out into Lake Onslows, pedestrian bridges over the Waitemata, insanely complicated and complex transport schemes whether they be roads or rail, or research reforms that stall without solutions. Saving more capacity in climate change research would at least aid the targeting process. Yet, it is not too much to ask for New Zealand to have the entire well-functioning research system it deserves.
Hi Troy – you needn’t have remained puzzled by the Lake Onslow proposal. After all, we were in the same tearoom together at Waikato University. I would have been happy to have a chat about it. It is most certainly not “obvious” that many smaller schemes would be better – see my reply to Kevin. This is not a plug for the Onslow scheme though – its cost has been quantified but we can’t pass judgement until its long-term national benefit has been quantified as well, with respect to a 100-year operational lifetime. It is, after all, a rather more significant piece of infrastructure than your pedestrian bridge. For the record, I can’t help thinking that in New Zealand “climate change research” has pretty much degenerated into paralysis by analysis. We actually need to start doing something. But like you, I’m a bit confused as to how the Lake Onslow scheme somehow got mixed into Kevin’s article comments. The scheme has in effect been put on hold by the present government, but it still generates strong comments that are often wildly incorrect. Perhaps at some point I should put together a more detailed item on the many aspects of the Onslow scheme, only some of which were picked up the the NZ Battery investigations.
spot on Kevin
but also the sideline comments on Onslow also illustrate that our political leadership have not a clue not just about what our future weather might look like, and its possible impacts, but about adaptation. Onslow is an idiotic idea that illustrates the complete lack of coherent big picture energy supply planning being undertaken at a national level. It also illustrates the fact that we are facing a multi-factor set of challenges – our first challenge is a political one – our decision makers (across the political spectrum) give a clear impression that they have no idea about the challenges we collectively face let alone having any answer to them. We have been effectively lacking any competent/coherent/impartial national strategic planning capacity to advise our political leadership for the past four decades since Roger Douglas destroyed the old public service.
Next we have an economic challenge, any solution to the issues ahead require imports of technology and materials and meanwhile we are already running a very substantial trade deficit – ie as a nation we are heading to being broke, we cannot afford to replace our vehicle fleet with EVs even if we wanted to;
We do not have a sane population (consumption) plan, our migration policies have added 2% to our population in the past year – we can not adapt at that rate; and most of the population increase adds far more to consumption (our carbon footprint and demand for imports) than it does to production;
we have a need to find alternatives to fossil fuel energy because regardless of its impacts on global climate, it is a finite resource that at some point in the not too far distant future will become increasingly expensive, there is also a strategic necessity to have some degree of energy self sufficiency – we are at the far end of the global supply chain for everything – a quick look at the global news indicates there are any number of ways that our imported energy supplies could be disrupted at short notice; imagine Auckland after a week with no petrol or diesel – there are plenty of imaginative interpretations of that scenario on netflix.
Hi Ciaran. Actually, giving consideration to an emission-free dry year buffer (whether Lake Onslow or something else) is a good example of big-picture long-term energy planning by the last government. Having a lot of extra on-call power generation capability is the best thing that we could do to offset the uncertainty of our climatic future. And yes, we absolutely do need to aim toward sustainable energy self sufficiency.
which is why dams on the lower clutha and lower waitaki are a far better idea – they generate far more power than Onslow and all of it additional generation – they would cost no more, they could be built much more rapidly and progressively bring additional generation on line. On top of that they would produce a minimum of 50% more energy yield from the existing hydro storages on these two river by increasing the number of generators utilising the stored water. Pumped storage has its place – indeed it is a really good idea but for off-setting imbalances in generation and demand over days and weeks – not years. The point I was making is that our political leadership has no strategic plan plan for our future energy needs including a rapid transition from imported fossil fuels – instead we have various interests pushing their own pet barrow/profitable opportunity meanwhile resulting in misdirected investment or policy paralysis – though it appears to be a mix of the two.
I guess in fairness to the previous government, they did at least initiate a strategic energy overview. The present regime seems more intent on leaving it to the market to sort out.
New Clutha and Waitaki dams as an Onslow alternative do not stack up in the numbers. Looking at the Waitaki, the “new dam” would be Meridian’s North Bank scheme. Project Aqua was soundly thrown out for environmental reasons. The total Waitaki scheme power increase from the North Bank scheme would be only about 10% – much less than the suggested 50%. I actually got to know the Waitaki scheme fairly well because for a number of years at the University of Waikato I held the rather verbose title of “Meridian Energy Senior Research Fellow in Applied Hydrology”.
The critical thing for dry years is having enough on-call power generation when needed. Pumped storage does not generate net power of course but can generate significant power for a duration. The Onslow scheme would have on-call generation of at least 1000 MW (for up to 6 months). The mean power output from the two present Clutha dams is 240 MW (Clyde) and 190 MW (Roxburgh). The expected power output from the North Bank scheme was 160 MW. The North Bank scheme coupled with doubling Clutha power output from new dams comes to a total of 590 new MW – well short of Onslow’s 1000 MW. Also, the 590 MW will be a considerable over-estimate because there is minimal hydro storage in Lake Hawea. This means that the Clutha River will have low flow in a dry year. That is, all the Clutha Dams (new + old) will be generating at much less than their mean MW outputs – and just when their power is needed in a dry year.
However, the inability of new hydro dams to be of help in a dry year does not mean that the Onslow scheme should be constructed. It’s a question of finding the best value for money as a long-term alternative to importing coal from Indonesia. It may be that the $13b multi-technology Onslow alternative comes out better overall, assuming investigations are re-started by a new government sometime in the future.
Incidentally, Onslow would not be just a dry year scheme. It would be operating in the electricity market at time scales of hours, days, weeks and seasons. It would be a continuous-operation dry year insurance infrastructure that would only rarely be used in that mode. Also, it wouldn’t be a single silver bullet. There will always be the rare risk of N dry years in row that would empty the upper reservoir when all the other hydro lakes are empty as well. Some backup against that would be needed – maybe gas in the first instance and perhaps later some new geothermal power. At all other times Onslow generation would be better because its power would be cheaper.
Earl, and others who are interested:
Thank you for the discussion. I’d make the same point in the opposite direction. I simply do not see the utility of the discussion you suggest for the reasons I outline here, also expressing reasons why disagree firmly with your response. There’s been a false premise that you seem to be repeating from what I can tell. I grew right in the catchment of a pumped hydroscheme in Maryland (USA) that played a big role in keeping grid there as renewable as NZ over recent decades with only a couple full days of capacity (little volume and head compared to what we have). Importantly, yes, the power is historically nuclear there, but the claim that we are fundamentally different is wrong. Our base of hydro is huge and the required generation could equally well be achieved with renewables here, and is shifting towards that in the Maryland region.
For NZ, we continue to have consented but unbuilt renewable capacity. Many issues including the unbuilt capacity can be solved by reform of the electricity market. Lake Onslow is foolishlish expensive if it is an alternative to that. I’ve never heard any reason to convince me Onslow, though technically possible and fascinating to some, is needed with sufficient renewable generation and existing hydro, or a bit more battery capacity to bridge diurnal/weekly/monthly gaps in wind and solar. For now a substantial amount of new capacity should be wind or geothermal for the obvious reason that solar isn’t crash hot in the middle of winter, but the dropping cost of solar is shifting that analysis quickly.
Ultimately, the failure to come to the same conclusion on this has little to do with the two of us talking in the tea room. I had high hopes for that tea room upon shifting to the University Waikato, but it turned out to be only scientists and engineers talking to each other with a more limited disciplinary mix than you’d find in the tea room most CRIs. I was extraordinarily disappointed by the culture at Waikato and the lack of connecting science with the excellence in planning and economics. Universities in general and Waikato in particular need to lift their game in this respect to overcome the inability of government evaluation and assessment to work through the big challenges (like the future of energy under climate change) we face as a nation. Internal criticism should sharpen arguments far more than has occurred in this case – which has become a national scale distraction.
But, perhaps the the original question that brought up Lake Onslow as a distraction is bang on about our problem as a nation, without articulating it perfectly. We tend to distract ourselves from solving the real problem at the pace that the nations we want to see as peers do. As Kevin makes clear in the op ed – we need science and research that is supported to properly frame the problem(s), and then build solutions.
Apologies Troy, but I can’t follow what you are saying in your first paragraph. I actually have no idea what is the “false premise” that I have supposedly been repeating, what “discussion” I have supposedly been suggesting, or what the “fundamental difference” is that I am supposedly claiming.
With respect to your other comments, Lake Onslow pumped storage has been proposed as one possible emission-free dry year solution. To my knowledge, it has never been advocated in the context of electricity market reform or unbuilt renewable capacity. Also, I can only assume that you are not being serious if you are suggesting that for dry years “a bit more battery capacity” is sufficient if combined with more wind and solar. More geothermal would be nice but the resource is limited.
I am not seeking to convince anyone that the Onslow scheme should proceed. Both Onslow and the multi-technology alternative are large and costly energy systems. Each has advantages and disadvantages. I hope that some future government will allow the final completion of the detailed business case reports for both options.
That’s it from me. Apologies Kevin for the Onslow diversion away from your original article. For anyone interested, an operating near-equivalent to the Onslow scheme is the Saurdal pumped storage scheme in Norway. Its specs, with the Onslow scheme equivalent in brackets, are: MW generating capacity: 640 (1000), TWh energy storage capacity in the upper reservoir: 3.3 (5), months of generating at maximum rate to empty the upper reservoir : 7 (6). The “dry year” in New Zealand does not mean 12 months of low inflows, but rather “a year with a few months of low inflows”. Hence a month is a useful time scale for long-term pumped storage.