Emissions plan is good, as far as it goes

As a climate scientist who worked in the United States for 42 years, I believe that I have a more global view of climate issues than most.  I have been prominent in the Intergovernmental Panel on Climate Change (IPCC) assessments and the World Climate Research Programme.  Now that I am back in New Zealand, I have taken a strong interest in how NZ deals with climate change.  Indeed, there is much that could be and needs to be done.  Which leads us to the government’s Emissions Reduction Plan, released on 16 May, 2022…

Major concerns about climate change in the 1980s led to the United Nations establishing an international treaty called the UNFCCC: The UN Framework Convention on Climate Change, signed in June 1992.  It was well understood then that the threats to the climate system were not from direct human influences, but rather stemmed from the human-induced changes in the atmospheric composition that interfered with the natural flows of energy through the climate system.  In particular, the use and burning of fossil fuels increases carbon dioxide in the atmosphere, and carbon dioxide is a greenhouse gas that contributes to global heating by forming a blanket layer over the Earth.  As carbon dioxide is long-lived (centuries) it builds up in concentrations in the atmosphere, so that current values of about 415 ppmv (parts per million by volume) are 48% higher than the pre-industrial value of 280 ppmv.  Half of that increase has occurred since 1985.  Other greenhouse gases, notably methane, are also rising in the atmosphere from human activities, although with a lifetime of only a decade or so.  Particulates, often called aerosols, are visible pollution that may block the sun and alter clouds, cause further complications. 

However, it was only in the late 1990s, in part through my own work, that it was understood that global heating had its biggest impacts through changes in extremes of weather and climate. This is because of the key role of water and the hydrological cycle on Earth.  Extra heat evaporates surface moisture, causing drying where not raining, but adding moisture to the atmosphere that can hold more moisture at a rate of 7% per degree Celsius, leading to heavier precipitation and risk of flooding.  Indeed droughts, heat waves and wildfires, at one end of the spectrum and more intense rains and heavier snows and flooding at the other end are now widely recognised to be occurring, with damage costs greatly amplified because of climate change.

The Paris Agreement in December 2015 under the UN framework sets emissions reduction targets and tracking, and reporting of progress towards meeting those targets.  This includes the goal of “holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C”.  The Paris Agreement also commits to enhancing adaptive capacity and resilience to the impacts of climate change. Six years on, most nations are failing to meet their commitments and emissions of greenhouse gases continue without diminution.  While many countries have significantly added renewable energy to their mix, demand for energy continues to rise.

A major concern of scientists, not adequately appreciated by the public and politicians, is that evidence of dangers warranting policy responses may be delayed or muted by the tremendous inertia in infrastructure and the climate system, so that by the time problems are abundantly clear, it may be too late to do anything about it.  The longer society delays taking steps to cut emissions of planet-warming greenhouse gases, the more severe and widespread the harm will be. While climate change has always been present, it is estimated that the current rates of change are more rapid than natural changes by a factor of hundred or greater.  It is the rates of change that are very disruptive, not only to natural ecosystems and biodiversity, but also to society. 

IPCC Reports

A new series of three IPCC reports has recently come out.  The first deals with science, the second impacts and adaptation, and the third mitigation: what can be done about it.  The first report from November 2021 stated

“Recent changes in climate are widespread, rapid, and intensifying, and unprecedented in thousands of years.”

It went on to say

“Unless there are immediate, rapid and largescale reductions in greenhouse gas emissions, limiting warming to 1.5°C will be beyond reach.”

The report itself is written over several years and statements are already out of date.  In particular, because it is evident that “rapid largescale reductions in greenhouse gases” are not occurring, the 1.5°C threshold is lost.  It is likely to be exceeded by about 2032.  Global agreements are not helped by a regional war and global pandemic.

This means that assessing vulnerability and past and expected impacts, and thus planning for expected consequences and adaptation to climate change is essential.  But it remains vital to also limit emissions and greatly slow future climate change to allow adaptation to occur and minimize disasters.

NZ emissions

This is the context for the NZ emissions plan.  NZ has a role to play as a leader in the South Pacific, as well as at home.  But it needs to be embedded in the global context.  The NZ emissions contribution is small and wiping it out would not solve the global problem.  But NZ can set an example, and apply pressure to other countries, such as Australia, China, and United States to get their houses in order.  This is an aspect missing from the plan.

The need is to decarbonize the economy, and especially the energy systems.  The new plan is to be highly commended in several areas, although the details matter.  There is excellent planning for improving emissions from transport, including buses, cars, and trucks, and encouraging cycling.  Huge gains can indeed be made through increased energy efficiency, both in industry and in housing and these initiatives are applauded.  Further gains have multiple benefits in managing waste and cutting methane emissions from landfills.   Adopting a holistic view that builds in needed biodiversity and resilience is also recommended.  There is also recognition that wood can be used as a renewable replacement for coal in some instances.  Wood and wood chips when burnt release carbon dioxide and other air pollution, but the carbon is replaced as new trees grow.  As discussed below, this may be important, but the forestry proposals are more sanguine.  The farming and agricultural emissions are misguided in my view. While some progress is readily viable and desirable, to be “first in the world” potentially puts NZ farmers at a huge disadvantage relative to others and in an adverse position in the marketplace until or unless international trade deals properly with tariffs for imports and exports involving carbon, and this seems some ways off.  Moreover, there are some notable omissions in the plan, especially with respect to solar, wind and hydro power, and how to deal with intermittency, see below.

NZ is already well placed through hydroelectric power but can do more.  Wind power is potentially abundant and is developing.  Solar power is also available and, although with less potential than in Queensland, prospects are far greater than for Germany, which is streets ahead, especially in rooftop solar along with net metering.  The issue with wind and solar power is intermittency, and NZ has been slow to address this (including in the Climate Commission). But coupling these power sources to hydro, whereby water is stored behind a dam, has tremendous potential except for the fragmented way that power companies work in NZ.  An integrated national approach is needed, and this is where the government should play a major role.   Nowadays, powerful batteries can be used, but a great under-utilized “battery” is pumped hydro.  This is being considered under the “Battery Project” by creating Lake Onslow down south but for the “dry year” problem, not for intermittency.  Instead much smaller and more local projects could be used as efficient batteries; many examples exist elsewhere such as in Switzerland and one is developing in Queensland.  In the latter case at Kidston, an old gold mine is used, and pumped hydro is planned for 250 MW with the height differential between the lower and upper lakes of only 230m.

Methane

Other greenhouse gases contribute to the global problem, notably methane.  As methane is a more potent green-house gas than CO₂, there is a lot to be gained in reducing atmospheric concentrations, as recognized at COP26 in late 2021 in Glasgow.  “Over 100 Nations at COP26 Pledge to Cut Global Methane Emissions by 30 Percent in Less Than a Decade” including New Zealand but not Australia.  The potential for reductions is huge for “fugitive emissions” that relate to methane vented into the atmosphere, leaks in pipes and abandoned mines, landfills, fracking operations and mining (drilling, extraction and transport) of coal, oil and natural gas.  In both Australia and NZ “agriculture”, which includes all cattle, dairy and sheep farming, makes up most methane emissions (70 to 110 Mt/year in Australia and 25 to 28 Mt/y in NZ).  But whereas fugitive emissions are 30 to 37 Mt/y in Australia, they are about 1 Mt/y in NZ.  In other words, the fugitive emissions in Australia exceed all of NZ’s emissions.  In the USA fugitive emissions run about 280 Mt/y.  Moreover, the scope to reduce those by tracking leaks and eliminating them is huge. 

Offsets

There has been a lot of hype about growing trees.  Indeed, trees take up carbon dioxide through photosynthesis and convert the carbon into the wood and plant material.  Trees also have many other desirable attributes, and the deforestation in the Amazon and elsewhere in the tropics has been a disaster.  Loss of carbon stored in forests and in the ground contributes to increases in atmospheric green-house gases.  Reforestation and expanding tree areas (afforestation) have potential to contribute to reduced atmospheric concentrations of carbon dioxide. 

Trees may grow faster with increased carbon dioxide in the air, but other factors, such as drought overwhelm those aspects.  Indeed, trees have a finite lifetime and are vulnerable to disease, drought, and wildfire.  They depend critically on adequate rainfall and water supply.  Several examples exist of trees set aside as “offsets” for carbon emissions that have been wiped out by wildfire.  It may be possible to achieve offsets for a specific date, such as 2050, but what happens in subsequent years as the trees saturate and die?  Indeed, an old-growth forest, almost by definition, is one that is neutral with regard to carbon dioxide, as the uptake in spring during photosynthesis is offset by the fall of leaves, twigs and dying trees especially in autumn, and forest floor decay. 

A key question is how to harvest mature trees and then grow new ones, and where and how to bury or sequester the old ones forever?  The new plan makes some progress by recognizing that wood can be used as a renewable biofuel replacement for fossil fuels, especially through wood chips, and these may also be exported.  While this puts pollution and carbon dioxide into the atmosphere, it is compensated for by the growth of new trees. But it is not then an offset.

In summary, there is a lot to like in the new emissions reduction plan, but more could be done, and there is insufficient recognition of what the rest of the world is (not) doing.