Showing results for: GHG impacts and mitigation
New Zealand’s Parliamentary Commissioner for the Environment has released a report exploring how much and over what timescale the climate is affected by methane emissions from livestock. It focused on two questions. First,if methane emissions from livestock were held at current levels or followed business-as-usual trajectories, what would their contribution to future warming be? Second, what reduction in methane emissions from livestock would be needed so that they cause no additional contribution to warming?
A recent paper uses data from volcanic eruptions to estimate the effects that geoengineering with sulphate aerosols would have on agricultural production. It concludes that the damage that geoengineering would do to maize, soy, rice and wheat outputs (because of reduction in sunlight reaching the crops) would have roughly the same magnitude as the benefits of the cooling it would provide.
A carbon tax applied across the whole economy, including agriculture, could put more people at risk of hunger (in terms of dietary energy availability) than climate change itself, according to a recent paper.
Researchers have warned that a cascade of positive feedback loops could push global temperatures into a “Hothouse Earth” state for millennia, even if human greenhouse gas emissions are reduced. Some systems, such as ice sheets, forests and permafrost, could pass a temperature tipping point beyond which they rapidly become net contributors to climate change. If one is set off, the warming produced could trigger the remaining tipping points, like a line of dominoes.
Farmers in Britain and other European countries have been affected by the ongoing heatwave and dry weather. Oxfordshire farmer Lesley Chandler told the Guardian, “It’s like a tinderbox out here… Just a spark could set it all alight” (read more here). Combine harvesters can create sparks if their blades hit a stone.
The FAO has released a report on the current state of knowledge on how climate change will affect fisheries and aquaculture, including mitigation and adaptation options. The report finds that “climate change will lead to significant changes in the availability and trade of fish products”. Marine catches could decrease by 2050 in the tropics and rise in some high latitude regions, with a global decrease in Exclusive Economic Zones of 3% to 12%. Inland fisheries in Pakistan, Iraq, Morocco and Spain may come under greater stress, while those in Myanmar, Cambodia, the Congo, the Central African Republic and Colombia may remain under low stress in the future.
Researchers from the University of Oxford’s Environmental Change Institute (of which the FCRN is part) have created a new tool - the “temperature of equivalence” - to map the impacts of varying degrees of climate change in different areas. They find that people living in low-income countries will, on average, experience heat extremes at 1.5°C of (global average) warming that people living high-income countries will not encounter until 3°C. This result is based on combining a map of predicted heat extremes with information on where people actually live within these areas. The paper also finds that, on average, people in high-income countries would experience the same increase in extreme rainfall after 1.0°C of warming that people in low-income countries would experience at 1.5°C of warming.
As global mean temperature rises due to climate change, the chance of multiple shocks in maize production occurring at the same time rises, due to greater variability in yields. The top four maize-producing countries are United States, China, Brazil, and Argentina. The chance of all four suffering a yield loss of more than 10% in the same year is presently almost zero, but rises to 6% for 2°C of warming and 87% for 4°C of warming. The study does not account for changing variability in temperature (only the increase in mean temperature), nor any gains from breeding heat-tolerant maize varieties.
The Centre for Ecoliteracy, a Californian non-profit, has produced a free interactive guide to understanding food and climate change, covering both how climate change affects the food system and how the food system contributes to climate change.
In a guest post for Carbon Brief, Professor Pete Smith of the University of Aberdeen discusses recent research on how climate mitigation through negative emissions could affect biodiversity, through changes in land use. He argues that bioenergy with carbon capture and storage (BECCS) should be implemented sooner rather than later, because of the risk of not meeting climate mitigation targets if BECCS is left until later in the century and because a study estimated that natural land loss could be lower if BECCS is deployed earlier in the century.
A paper proposes a new method for evaluating the climate impact of short-lived greenhouse gases (GHGs) such as methane. Different GHGs are currently assessed on the basis of global warming potential (GWP), calculated as carbon dioxide equivalent, usually over a 100 year time horizon. The paper authors say that this misrepresents the impact of short-lived GHGs, because they have stronger climate impacts shortly after being released and lower impacts after being in the atmosphere for some time.
The Hoffmann Centre at UK think tank Chatham House has produced a summary of a workshop held in January 2018 on policy implications of widespread deployment of negative emissions technologies. The workshop concluded that bioenergy with carbon capture and storage (BECCS) cannot be used at the scale assumed in emissions pathways compliant with the Paris agreement, because it would cause large land use change in regions of high biodiversity and compete with food production for land. Nevertheless, some BECCS may be needed. Direct air capture would use less land than BECCS, but there are economic and technical barriers.
A new paper examines how both climate change and land use could affect future biodiversity. It finds that, by 2070, climate change could become a greater driver of species loss than land use change. Climate change alone could cause species loss of 11% to 29% relative to 1961-1960, depending on the severity of temperature rise.
FCRN member Eric Toensmeier, of Yale University, has written an op-ed for the Washington Post in which he discusses the potential of silvopasture - including trees on grazing land - to reduce agricultural emissions. Trees increase production by providing shade to livestock, according to the op-ed.
FCRN member Ramy Salemdeeb of Ricardo Energy & Environment used Life Cycle Assessment to calculate 14 different categories of environmental impacts of three food waste management options: incineration, composting and anaerobic digestion. Composting had the lowest impacts in 7 out of the 14 impact categories.
Fresh fruit and vegetables deliberately withdrawn from the market and destroyed under the EU’s Common Agricultural Policy accounted for 5.1 Mt CO2 eq. in embedded production-stage emissions between 1989 and 2015, according to research by FCRN member Stephen Porter of the University of Edinburgh.
173 countries have agreed to halve emissions from the global shipping industry by 2050, compared to 2008 levels, in a non-binding deal arranged by the International Maritime Organisation. Saudi Arabia, the US and several other countries raised objections to the proposed emissions cuts. Shipping was not covered by the 2015 Paris agreement on climate change.