Climate explained: how climate change will affect food production and security


Many temperate crops require winter chilling to initiate flowering or fruit ripening, and orchards may need to shift to colder areas.
from http://www.shutterstock.com, CC BY-ND

Julian Heyes, Massey University


CC BY-ND

Climate Explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.

If you have a question you’d like an expert to answer, please send it to climate.change@stuff.co.nz

According to the United Nations, food shortages are a threat due to climate change. Are food shortages a major threat to New Zealand due to climate change?

Climate change is altering conditions that sustain food production, with cascading consequences for food security and global economies. Recent research evaluated the simultaneous impacts of climate change on agriculture and marine fisheries globally.

Modelling of those impacts under a business-as-usual carbon emission scenario suggested about 90% of the world’s population – most of whom live in the least developed countries – will experience reductions in food production this century.

New Zealanders are fortunate to live in a part of the world blessed with relatively fertile soils, adequate water supplies and mild temperatures. This gives us a comparative advantage for agriculture and horticulture over many other countries, including our main trading partner, Australia.

New Zealand produces more than enough food for its population. Exports exceed local consumption, and climate-change induced food shortages should not be an imminent risk for New Zealand. But behind every general statement like this lies some rather more troubling detail.




Read more:
Feeding the world: archaeology can help us learn from history to build a sustainable future for food


Overcoming domestic challenges

As residents of a developed country, we are accustomed to accessing the world’s resources through supermarkets. New Zealanders take for granted that most foods (even those we do not produce, like rice or bananas) will be available all year round.

Asparagus, new potatoes and strawberries are examples of foods New Zealanders may expect to see only at particular times of the year, but if apples or kiwifruit are out of stock, people usually complain. Our expectations are based on imports of products when they are out of season in New Zealand. The availability of those imports may be seriously compromised by climate change.

A recent Ministry for the Environment report describes climate impacts, including detailed projections of the average temperature increase and changes in rainfall patterns across New Zealand. The consistent trends are towards wetter conditions in the west, drier in the east and the largest average temperature rises in the north.

Implications for agriculture are manifold. For example, many temperate crops require cool autumn or winter temperatures to initiate flowering or fruit ripening. Orchards may need to be relocated further south, or novel low-chill varieties may need to be bred, as is already happening around the world.




Read more:
Climate explained: regenerative farming can help grow food with less impact


Insect pests and diseases are normally controlled by our low winter temperatures, but they may become more of a problem in the future. Introduced pests and diseases include fruit flies that have a major impact in Australia and other more tropical countries, but struggle to establish breeding colonies in New Zealand. Strong biosecurity controls are our best bet for reducing this risk.

What matters more than the gradual increase in temperature predicted by climate change models, is the greater frequency of extreme weather events. These include droughts, floods and hail, which can lead to total crop losses in particular regions. One obvious mitigation strategy is to expand the provision of irrigation in our drier eastern regions, but concerns over water quality in our rivers mean this is not a popular option with the public – for example on the Heretaunga Plains or in Canterbury.

Risks to imported products

New Zealand is a net exporter of dairy, beef, lamb and many fruit and vegetables, but for some products, we depend heavily on imports. Figures from the US Department of Agriculture are not perfect, but they highlight trade imbalances for major commodities.

New Zealand imports all rice and most of its wheat. It is a net importer of pork products. Horticultural data released annually in Fresh Facts show New Zealand’s major horticultural imports are (in order of value) wine, nuts, processed vegetables, coffee, bananas and table grapes. These imported products come primarily from Australia, China, the US and Ecuador – all countries that may be less resilient to climate change than New Zealand.

As a recent report by the UN Food and Agriculture Organisation (FAO) explains, rising temperatures, rising seas and the increasing frequency of adverse weather events will interact to reduce agricultural and horticultural productivity in many regions around the world. While New Zealand is unlikely to experience food shortages in the near future as a direct result of climate change, the price and availability of imported products may increase significantly.




Read more:
Feeding cities in the 21st century: why urban-fringe farming is vital for food resilience


Food poverty

Unfortunately, there is another important consideration. Some New Zealanders already experience food insecurity. The 2008/9 Adult Nutrition Survey found 14% of New Zealand households reported running out of food often or sometimes due to lack of money.

Perhaps rather than worrying about the future impact of climate change on the price or availability of imported rice or bananas, we should be paying more attention to this social inequity.

As a wealthy agricultural nation and a net exporter of food, it does not seem right that one sector of our society is already regularly experiencing food shortages.The Conversation

Julian Heyes, Head of School of Food and Advanced Technology@ISHS_CMFV, Massey University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Methane from food production might be the next wildcard in climate change


Pep Canadell, CSIRO; Ben Poulter, NASA; Marielle Saunois, Institut Pierre-Simon Laplace; Paul Krummel, CSIRO; Philippe Bousquet, Université de Versailles Saint-Quentin en Yvelines – Université Paris-Saclay , and Rob Jackson, Stanford University

Methane concentrations in the atmosphere are growing faster than any time in the past 20 years. The increase is largely driven by the growth in food production, according to the Global Methane Budget released today. Methane is contributing less to global warming than carbon dioxide (CO₂), but it is a very powerful greenhouse gas.

Since 2014, methane concentrations in the atmosphere have begun to track the most carbon-intensive pathways developed for the 21st century by the Intergovernmental Panel on Climate Change (IPCC).

The growth of methane emissions from human activities comes at a time when CO₂ emissions from burning fossil fuels have stalled over the past three years.

If these trends continue, methane growth could become a dangerous climate wildcard, overwhelming efforts to reduce CO₂ in the short term.

Methane concentration pathways from IPCC and observations from the NOAA measuring network (Saunois et al 2016, Environmental Research Letters). The projected global warming range by the year 2100, relative to 1850-1900, is shown for each pathway.

In two papers published today (see here and here), we bring together the most comprehensive ensemble of data and models to build a complete picture of methane and where it is going – the global methane budget. This includes all major natural and human sources of methane, and the places where it ends up in methane “sinks” such as the atmosphere and the land.

This work is a companion effort to the global CO₂ budget published annually, both by international scientists under the Global Carbon Project.

Where does all the methane go?

Methane is emitted from multiple sources, mostly from land, and accumulates in the atmosphere. In our greenhouse gas budgets, we look at two important numbers.

First, we look at emissions (which activities are producing greenhouse gases).

Second, we look at where this gas ends up. The important quantity here is the accumulation (concentration) of methane in the atmosphere, which leads to global warming. The accumulation results from the difference between total emissions and the destruction of methane in the atmosphere and uptake by soil bacteria.

CO₂ emissions take centre stage in most discussions to limit climate change. The focus is well justified, given that CO₂ is responsible for more than 80% of global warming due to greenhouse gases. The concentration of CO₂ in the atmosphere (now around 400 parts per million) has risen by 44% since the Industrial Revolution (around the year 1750).

While CO₂ in the atmosphere has increased steadily, methane concentrations grew relatively slowly throughout the 2000s, but since 2007 have grown ten times faster. Methane increased faster still in 2014 and 2015.

Remarkably, this growth is occurring on top of methane concentrations that are already 150% higher than at the start of the Industrial Revolution (now around 1,834 parts per billion).

The global methane budget is important for other reasons too: it is less well understood than the CO₂ budget and is influenced to a much greater extent by a wide variety of human activities. About 60% of all methane emissions come from human actions.

These include living sources – such as livestock, rice paddies and landfills – and fossil fuel sources, such as emissions during the extraction and use of coal, oil and natural gas.

We know less about natural sources of methane, such as those from wetlands, permafrost, termites and geological seeps.

Biomass and biofuel burning originates from both human and natural fires.

Global methane budget 2003-2012 based on Saunois et al. 2016, Earth System Science Data. See the Global Carbon Atlas at http://www.globalcarbonatlas.org.

Given the rapid increase in methane concentrations in the atmosphere, what factors are responsible for its increase?

Uncovering the causes

Scientists are still uncovering the reasons for the rise. Possibilities include: increased emissions from agriculture, particularly from rice and cattle production; emissions from tropical and northern wetlands; and greater losses during the extraction and use of fossil fuels, such as from fracking in the United States. Changes in how much methane is destroyed in the atmosphere might also be a contributor.

Our approach shows an emerging and consistent picture, with a suggested dominant source along with other contributing secondary sources.

First, carbon isotopes suggest a stronger contribution from living sources than from fossil fuels. These isotopes reflect the weights of carbon atoms in methane from different sources. Methane from fossil fuel use also increased, but evidently not by as much as from living sources.

Second, our analysis suggests that the tropics were a dominant contributor to the atmospheric growth. This is consistent with the vast agricultural development and wetland areas found there (and consistent with increased emissions from living sources).

This also excludes a dominant role for fossil fuels, which we would expect to be concentrated in temperate regions such as the US and China. Those emissions have increased, but not by as much as from tropical and living sources.

Third, state-of-the-art global wetland models show little evidence for any significant increase in wetland emissions over the study period.

The overall chain of evidence suggests that agriculture, including livestock, is likely to be a dominant cause of the rapid increase in methane concentrations. This is consistent with increased emissions reported by the Food and Agriculture Organisation and does not exclude the role of other sources.

Remarkably, there is still a gap between what we know about methane emissions and methane concentrations in the atmosphere. If we add all the methane emissions estimated with data inventories and models, we get a number bigger than the one consistent with the growth in methane concentrations. This highlights the need for better accounting and reporting of methane emissions.

We also don’t know enough about emissions from wetlands, thawing permafrost and the destruction of methane in the atmosphere.

The way forward

At a time when global CO₂ emissions from fossil fuels and industry have stalled for three consecutive years, the upward methane trend we highlight in our new papers is unwelcome news. Food production will continue to grow strongly to meet the demands of a growing global population and to feed a growing global middle class keen on diets richer in meat.

However, unlike CO₂, which remains in the atmosphere for centuries, a molecule of methane lasts only about 10 years.

This, combined with methane’s super global warming potency, means we have a massive opportunity. If we cut methane emissions now, this will have a rapid impact on methane concentrations in the atmosphere, and therefore on global warming.

There are large global and domestic efforts to support more climate-friendly food production with many successes, ample opportunities for improvement, and potential game-changers.

However, current efforts are insufficient if we are to follow pathways consistent with keeping global warming to below 2℃. Reducing methane emissions needs to become a prevalent feature in the global pursuit of the sustainable future outlined in the Paris Agreement.

The Conversation

Pep Canadell, CSIRO Scientist, and Executive Director of the Global Carbon Project, CSIRO; Ben Poulter, Research scientist, NASA; Marielle Saunois, Enseignant chercheur à l’Université de Versailles Saint Quentin; chercheur au Laboratoire des Sciences du Climat et de l’Environnement, Institut Pierre-Simon Laplace; Paul Krummel, Research Group Leader, CSIRO; Philippe Bousquet, Professeur à l’université de Versailles Saint-Quentin en Yvelines, chercheur au Laboratoire des sciences du climat et de l’environnement (LSCE), membre de l’Institut de France, auteur contributif d’un chapitre des deux derniers rapports du GIEC, Université de Versailles Saint-Quentin en Yvelines – Université Paris-Saclay , and Rob Jackson, Professor, Earth System Science and Chair of the Global Carbon Project, Stanford University

This article was originally published on The Conversation. Read the original article.

Australia: Carbon Price Needed Now


Thirteen of Australia’s leading economists have signed and published an open letter calling for a speedy introduction of a carbon price for carbon polluters. They prefer to have a carbon emissions trading scheme institututed as soon as possible.

The introduction of carbon pricing is designed to accelerate a move to more environmentally friendly production methods, increased reliance on renewable energy sources, etc.

For more visit:
http://theconversation.edu.au/economists-open-letter-calls-for-carbon-price-1639

View the actual letter.

 

Renewable Energy: Massive Wind Power Project in Texas


The following link is to an article on a major wind power project in Texas, USA. The technology being developed as part of this scheme could be of major importance for energy production and storage around the world. Being able to store electricity generated by wind power in massive batteries is an interesting development.

For more visit:
http://www.grist.org/wind-power/2011-04-15-no-trees-big-battery-texas-to-install-worlds-largest-wind