New paper suggests no warming in NZ in past 100 years

New Zealand may not have warmed at all in the past 100 years, according to a peer-reviewed paper published in the international science journal, Environmental Modeling & Assessment.

The paper, “A Reanalysis of Long-Term Surface Air Temperature Trends in New Zealand,” by New Zealand authors, Chris De Freitas, Bob Dedekind and Barry Brill, covered the period 1909-2009. It shows an increase of 0.28 degrees C, +/- 0.29 degrees/century, compared with the current official NIWA 7-station (7SS) series showing an increase of nearly 1 degree C.

The government must take this new finding into account in future climate policy development, says Prof Robert M. Carter, a graduate of Otago University and Honorary Fellow of the Royal Society of New Zealand.

Professor Carter explains:

“To place a rate of warming of 0.28 deg. C in context, extensive geological data sets show that rates of temperature change have varied naturally by up to plus and minus 2.5 deg. C/century during the last 10,000 years (i.e., through the interglacial warm period that we currently live in). In other words, pre-historic rates of natural change exceeded the warming in New Zealand over the last century by as much as 10 times.

“Furthermore, the margin for error associated with de Freitas et al.’s warming estimate is plus or minus 0.29 deg. C/century. In other words, statistically, this is indistinguishable from no warming at all in New Zealand over the last 100 years.

In 1980, Dr M.J. Salinger applied a new statistical technique of homogenisation to the period of New Zealand record between 1853 and 1975, using data from seven geographically spread observing stations. This seven-station series (7SS) showed a rate of warming of about 1 deg. C/century, a figure that has been widely factored into climate policy determinations in New Zealand.

In this new paper, the authors have undertaken an updated reanalysis of the 7SS record. They say they have followed strictly the statistical technique pioneered by Salinger (as published in a paper by Rhoades & Salinger in 1993), though incorporating subsequent data corrections identified in the scientific literature, and provide a detailed schedule of the adjustments that were made in their analysis.

The full paper can be read here.

One thought on “New paper suggests no warming in NZ in past 100 years

  1. First it was global cooling, then global warming, then it was climate change now there has been no warming at all, so no need to worry!

    Although it is commendable that the authors of this article have gone to the trouble of recalculating land surface temperature data for New Zealand over the last 100 years, it is articles such as these that seed complacency in peoples minds, potentially breeds distrust in science and are unhelpful for policy development as it implies that we don’t need to aim high with regard to setting meaningful environmental targets.

    The announcement of the mini-ice age last week and associated comments from the public is an obvious example of how research such as this can be twisted by the mainstream media – all of a sudden you have a reason to be complacent because, shock horror, global warming will turn into global cooling! (If that research paper is actually read it says that there will potentially be large declines in sunspot activity, which will fractionally decrease the energy output of the sun leading to less radiation reaching earth.) Whether this is true or not, and whether this will actually have a substantial impact on earths climate is almost irrelevant! It should not distract from the fact that we as humans are treating the planet as a sewer, nor it does not change the fact that it is impossible to “grow” indefinitely on a planet with finite resources. Like it or not we need to change our ways yesterday! As a microbiologist I see parallels between the current earth/burgeoning human population with bacteria growing on a petri dish – it doesn’t end that well for the bacteria as they eventually use up their resources and trash there environment so much that they are forced into survival mode eating the remains of each other to recycle the meager resources left.

    Happy consuming everybody!

    The potential way this new research will be presented by the mainstream media will undoubtedly be translated by the general public as yet another reason we don’t need to change our ways. However, given what’s occurring in the Arctic and Northern Hemisphere right now we are already in deep trouble – fracturing of the jet-stream and associated climate extremes (heat-waves and cold shocks), shallow sea methane plumes growing in size, melting permafrost and associated C/methane releases, catastrophic loss of sea-ice volume etc.) Like it or not what happens in the arctic affects the globe and the chickens will eventually come home to roost in NZ. The global mean temperature is rising and possibly accelerating and just because it doesn’t appear to be currently happening in NZ is no reason for us not to act immediately.

    If this new research is correct then it suggests climate ‘warming’ may not have occurred in NZ for the last 100 years, but I believe this research is erroneously presented because it does not adequately address the global context. The negative effects of climate change are now clearly evident around the globe and it certainly seems that extremes in weather are beginning to become more frequent here. Despite climate scientists saying that singular events can’t easily be linked to climate change, even in my lifetime there has been an obvious change in isolated extreme events such as floods. Admittedly, for the NZ scenario recently, some of this can be put down to El Nino conditions which is having a significant impact this winter as El Nino leads to a general increase the S to SW type flows (cold and wet) over NZ during the winter but also note that we are likely to have more westerly air flows during the summer i.e. prepare for East coast drought. If the predictions are correct, we are looking at a super El Nino event this year that will dwarf the one in 1998.

    To continue on this thread, I don’t think there is any coincidence that we are expecting a monster El Nino and the fact that the oceans are exceptionally warm not just unusually warm. The so-called pause in land surface warming completely disappears when an energy balance is calculated that includes heat in the oceans. Analyzing land surface temperature records without adequately addressing the overall global energy imbalance in both the atmosphere and hydrosphere is misleading, and it is very nonconstructive for the authors to suggest that policy be reevaluated because the land surface temperatures in NZ happen to have not changed over the last 100 years.

    Long story short, just because NZ supposedly hasn’t warmed doesn’t mean the overall global picture is any less frightening… it’s crazy out there and we should prepare for the worst even if it doesn’t eventuate.


    Craig Anderson

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