It may be winter here, but Guy Trafford can't help but notice Northern Hemisphere heat waves and he wonders what our summer may have in store

Given that we are in the pits pf winter it seems somewhat premature to the thinking about what summer may bring us in five or six months. However, given the steady media diet of heat waves and wildfires coming out of the Northern Hemisphere plus floods from across in Australia, the weather patterns are hard to ignore.

Just because Europe and others are experiencing record temperatures does not necessarily mean that we are in for the same here. Last year for many kiwis the weather was dominated by rainfall rather than extreme heat or drought, Southland being the exception.

So, what are the experts predicting for this coming summer?

Firstly, a lot can change in forecasts between now and then, however they seem to agree and with ‘high degrees’ of confidence on one thing, it is going to be warmer than average.

Actually, despite last summer not being a memorable one for sunshine it was still the 5th warmest on record and with a high of 34.7^oC (Lake Karapiro).

The UK, not usually noted for its weather, has already hit 38.1^oC (its record is 38.7^oC set in 2003 so quite away ahead of New Zealand - oops as of today 40.2^oC).

Largely the New Zealand temperatures are driven by our surrounding ocean, and we are still in the midst of a marine heatwave with water temperatures between 0.7^oC and 1.9^oC above average and our land temperatures are bound to increase. This in turn is driven by the La Niña oscillation phase we are still in. NIWA are predicting quite a high likelihood of this persisting into its third summer, not unheard of but relatively unusual.

This does not guarantee that the up coming season will be the same as the last but we can be assured it is going to be warm, the question is; just how warm?

The NIWA graphics below do look rather dramatic with the whole country in deep red. However, it is the July to September period and no temperatures estimates are attached.

Source: NIWA July 2022

For farmers, anything away from what is considered normal (or average) can be an issue for stress although most pastoral farmers don’t mind a bit more rainfall than average over the summer, its just not great for the arable and horticulture sectors.

If the season tracks more like what we are seeing in the north hemisphere, then there is reason to be concerned. Heatwaves interrupted by heavy deluges are good for no one and animals in particular can suffer.

Ironically in the Canterbury and other widely irrigated areas, farmers are required to meet ‘best practise’ guidelines when they sign up to irrigation schemes and the like. Unfortunately, ‘best practise’ in regards to irrigation revolves around limiting excess water runoff and wasteful drainage thereby reducing the flow of N and P into waterways and aquifers.

To get the control required to meet best practise has generally meant that there has been the widespread removal of trees on and around pasture land as the large centre pivot and long lateral irrigators are the best set up for the finer controls provide by computer programmes and savings in labour. Rotor-rainers and the similar smaller irrigators have, through the drive to greater efficiencies, gone into the annals of history. Along with them many shelter belts and shade giving trees.

If the temperatures through the summer go as predicted then increasingly animal welfare is going to become an issue and farmers will yet again be on the receiving end of societies ire. Yet another reason that some form of barn or shelter are incorporated into livestock systems.

Frustratingly, given that world emissions are still on the increase and when countries such as the US has courts which ruled against the science and reduces the ability of the Federal Government to curb emissions, you know that for a large part of the world’s population we are going to have to learn to life with the effects of climate change for our ‘natural’. Hopefully, children born now will see some improvement in their lifetimes.

When it comes to mitigating against the impacts of climate, a piece on the national news which covered the story of Canterbury coastal farmers facing being inundated by the ocean and the lack of support from the regional council may be a sign of things to come. Local bodies and central government alike are going to have to pick their battles carefully in the future especially when it comes to coastal inundation given the cost and potential scale of the problem around New Zealand.

On the brighter side at least the level of lakes used to provide hydro electricity are at good levels. National hydro storage stayed constant at 90% of the historical average for this time of year (July 13th, 2022). North Island hydro storage decreased by 7% to 155% of the historical average. South Island storage remains at 83% of the historical average for this time of year (after the last 48 hours they are likely to exceed this now). So, the country should be in good stead to run both irrigators and air conditioners if the need requires. Currently it also means that the ‘spot price’ for power has also reduced.