By Kevin Trenberth

Climate change is a global problem requiring a global solution, but individual nations like New Zealand can play a role and must do so, writes Kevin Trenberth.

The climate is changing and human activities are the cause: this is confirmed in the latest report from the Intergovernmental Panel on Climate Change, the United Nations body that assesses climate change science and on which I have played a major role in the past.

“Recent changes in the climate are widespread, rapid, and intensifying, and unprecedented in thousands of years”, says the IPCC report of November 2021.

“It is indisputable that human activities are causing climate change, making extreme climate events, including heat waves, heavy rainfall, and droughts, more frequent and severe.”

So why is climate change so bad? After all, people live comfortably in a wide range of climates from the tropics to the Arctic. But it is the “change” aspect that is disruptive, it alters what we are adapted to, especially for farming and growing food. Moreover, evidence shows this change is making extreme weather events worse with large loss of life, costs in the billions of dollars and regional disruptions that last for years.

Everyone must act to slow down and even stop climate change – because the main cause of global climate change is the changing composition of the atmosphere, especially from the buildup of long-lived carbon dioxide mainly from burning fossil fuels, the solution is to reduce emissions.

Climate change in action

The main cause of global climate change is the changing composition of the atmosphere, especially the buildup of carbon dioxide from burning fossil fuels, and also from other greenhouse gases such as methane, nitrous oxide and chlorofluorocarbons.

These gases are heating the planet and this has consequences. The global mean surface temperature has increased by 1.1°C since the 1800s (pre-industrial times) and sea temperatures are higher. The extra heat increases evaporation and drying when water is present, placing more water vapour into the atmosphere. In places where it is not raining, land dries out, increasing drought and the risk of heat waves and wildfires.

Where it does rain, the extra moisture is swept up into storms and it rains harder. Or it snows harder. Moreover, as precipitation is produced, it releases the latent heat that went into the evaporation in the first place and strengthens the storm. Hurricanes become more active and storms are more intense, longer-lasting and more frequent and with more extreme rainfalls. These factors can be additive and have led to 30 percent more rain in several events. In the winter half year, thunderstorms get a boost which increases the odds of a tornado outbreak, such as occurred recently in Kentucky and surrounding areas. At least 50 tornadoes across eight states destroyed homes and businesses and likely killed more than 100 people. All are linked to climate change.

The public generally does not realise that these diverse events are part of a pattern of change that is progressively getting worse and more widespread. But climate scientists are worried.

A global crisis requires a global solution

In November NASA launched a new satellite DART designed to test bumping an incoming meteor-like object off course so that it won’t hit the Earth. This is a trial run to see whether it is possible to prevent a global catastrophe.

But where is the NASA spaceship to bump us back on course with the very real crisis we are facing with regard to climate change?

Back in 1992 climate change concerns led to the international United Nations Framework Convention on Climate Change (UNFCCC) that went into effect in 1994 to combat “dangerous human interference with the climate system”. As well as requiring countries to report on emissions, it instigated the annual Conference of the Parties (COP), led to the Kyoto Protocol in 1997 and then, in December 2015, the Paris Agreement. COP26 was recently held in Glasgow to reinforce the Paris Agreement, but results were underwhelming.

There is widespread belief among scientists that not enough is being done to curb climate change and that it could result in an existential threat to civilisation. By the time global temperatures have reached 2°C above preindustrial, expected for the 2050s, extreme weather events will be common, crops that grow now may not be viable, trees will not grow back, water shortages will become widespread and food will be in short supply. As a result, there will be widespread numbers of environmental refugees, exacerbating tensions and likely leading to regional conflicts in many countries.

Any pandemic will further aggravate these problems. How all this plays out is far from clear, but the threats are real.

We are all passengers on spaceship Earth. Yet there is no captain to make decisions, and no viable international governance. The closest we have is the UN, a weak body that requires unanimous consensus to pass anything and many countries do not abide by its mandates. Even the International Court of Justice, established in 1945, is not recognized by some countries which insist on their own jurisdiction.

New Zealand’s role

So where does that leave New Zealand? New Zealand can’t impose its views elsewhere but can set a good example and look out for its smaller neighbours, as it does. It can become more sustainable and encourage natural systems and biodiversity. In other words, do things that matter for New Zealanders, regardless of climate change.

But we have been very slow to act in reducing emissions. Attention has gone on New Zealand’s unusual greenhouse gas profile of having as much emissions from methane as from carbon dioxide. Most of those emissions are from agriculture, especially dairy, cattle and sheep farming. Methane has an average lifetime of just nine years and reducing emissions has a quick payoff. This was recognised at COP26 and an agreement reached and signed, including by NZ.

However, other countries are not reducing biogenic methane, but rather focusing on “natural gas” from mining, fracking, leaky wells, flaring off or venting of surplus gas, and leaky pipelines. These are called fugitive emissions, most are found and dealt with easily; reduced losses paying for the costs. In contrast, although gains seem possible from farming, they may impact food production and are at best modest unless stock is reduced. Australia has more fugitive emissions of methane than all of NZ’s methane emissions together. Pressure on NZ farmers benefits Australian and other farmers around the world.

New Zealand has mostly adopted an approach of “offsets” but not noticeably reduced emissions, and atmospheric greenhouse gas concentrations continue to grow at record pace. Emissions could be reduced by cutting coal-fired power stations and promoting renewable wind, solar and hydro power, and decarbonising the economy. Solar and wind are now cost effective, but a system-wide approach is required to address intermittency of these systems, and this can be readily done when coupled to hydro-dam storage of water.

New Zealand has made commitments but so far not stepped up with plans to meet them. We can do it.

This article was originally published on Newsroom and was republished with permission. For the original, click here.

Kevin Trenberth is an internationally recognised expert on climate change and honorary academic at the Faculty of Science, University of Auckland. 

Disclaimer: The ideas expressed in this article reflect the author’s views and not necessarily the views of The Big Q.

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