Showing results for: Climate trends/projections
The US Global Change Research Programme has published the second volume of its Fourth National Climate Assessment, which examines the human welfare, societal, and environmental impacts of climate change and variability across many sectors, including agriculture.
Losses of wheat, rice and maize to insects could increase by 10 to 25% per degree Celsius of climate warming, according to this paper. This is due to two main factors: insects have faster metabolisms at higher temperatures and therefore need to eat more; and insect population growth rates will also change with temperature.
The Intergovernmental Panel on Climate Change (IPCC) has released a special report on keeping climate change to 1.5°C. The report says, “Limiting global warming to 1.5°C would require rapid, far-reaching and unprecedented changes in all aspects of society.”
A global model of how child stunting could be affected by climate change and poverty in 2030 has been developed by FCRN member Simon Lloyd of the London School of Hygiene and Tropical Medicine. By 2030, an estimated 570,000 to over one million children under 5 will suffer from stunting that can be attributed to climate change, with both greater poverty and greater climate change causing more stunting.
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.
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.
The UK’s Committee on Climate Change has released its 2018 Progress Report to Parliament on Reducing UK Emissions. Chapter 6 focuses on agriculture and land use, land-use change and forestry. The report finds the UK agricultural emissions were unchanged between 2008 and 2016. In 2017, half of farmers did not think it was important to consider emissions when making decisions about farming practices. The forestry sector’s ability to sequester carbon has levelled off due to the average age of trees increasing relative to the past. Chapter 6 makes only passing reference to demand-side measures for agricultural emissions reductions (see Figure 6.9).
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.
600 million people could be affected as climate change decreases the levels of several nutrients in rice, according to a new paper. The paper estimated changes in rice nutrient content using experiments where rice (of several different cultivars) was grown under conditions of enriched CO2. At the higher CO2 levels, the following average decreases in nutrient levels were found compared to rice grown under ambient CO2: 10% for protein; 8% for iron; 5% for zinc; 17% for vitamin B1; 17% for vitamin B2; 13% for vitamin B5; 30% for vitamin B9. In contrast, vitamin E levels were 14% higher under elevated CO2 levels.
Researchers from Nasa have used satellite data to identify areas where freshwater reserves have increased or decreased. The study found that in 14 regions, the changes were likely due to human factors (e.g. groundwater pumping), and in 8 areas, the changes were caused mainly by climate (e.g. drought or ice-sheet melting). Freshwater availability decreased in several areas including northern India, north-east China, the Caspian and Aral Seas and some of the Middle East.
The planetary boundaries concept provides a theoretical upper limit on human activity which the planet is able to sustain without major perturbation to the current ‘Earth system’. Previously, nine planetary boundaries (PBs) have been proposed and recently Steffen et al. (2015) have updated these boundary definitions and assessed the current state of the position of human activity with respect to each boundary. In this article, researchers from a number of food, climate change, agricultural and environmental research institutions around the world build on this work by assessing the impact of agriculture on each PB status, based on a detailed literature review of the available research.
Countries attending FAO’s 40th conference in Rome discussed climate change and food security from different perspectives linking climate-action, nutrition and migration to the 2030 Agenda for Sustainable Development. Four side events related to climate change took place during this conference, which can now be watched online.