1 March 2017, The Conversation, As global food demand rises, climate change is hitting our staple crops. While increases in population and wealth will lift global demand for food by up to 70% by 2050, agriculture is already feeling the effects of climate change. This is expected to continue in coming decades. Scientists and farmers will need to act on multiple fronts to counter falling crop yields and feed more people. As with previous agricultural revolutions, we need a new set of plant characteristics to meet the challenge. When it comes to the staple crops – wheat, rice, maize, soybean, barley and sorghum – research has found changes in rainfall and temperature explain about 30% of the yearly variation in agricultural yields. All six crops responded negatively to increasing temperatures – most likely associated with increases in crop development rates and water stress. In particular, wheat, maize and barley show a negative response to increased temperatures. But, overall, rainfall trends had only minor effects on crop yields in these studies. Since 1950, average global temperatures have risen by roughly 0.13°C per decade. An even faster rate of roughly 0.2°C of warming per decade is expected over the next few decades. As temperatures rise, rainfall patterns change. Increased heat also leads to greater evaporation and surface drying, which further intensifies and prolongs droughts. A warmer atmosphere can also hold more water – about 7% more water vapour for every 1°C increase in temperature. This ultimately results in storms with more intense rainfall. A review of rainfall patterns shows changes in the amount of rainfall everywhere. Read More here
Yearly Archives: 2017
1 March 2017, Climate News Network, Spring moving forward at record rate. Spring is arriving ever earlier in the northern hemisphere. One sedge species in Greenland is now springing to growth 26 days earlier than it did a decade ago. And in the wintry United States, spring arrived 22 days early this year in Washington DC, the national capital.The evidence comes from those silent witnesses, the natural things that respond to climate signals. The relatively new science of phenology – the calendar record of first bud, first flower, first nesting behaviour and first migrant arrivals – has over the last three decades repeatedly confirmed meteorological fears of global warming as a consequence of the combustion of fossil fuels. Researchers say the evidence from the plant world is consistent with the instrumental record: 2016 was the hottest year ever recorded, and it was the third record-breaking year in succession. Sixteen of the hottest years ever recorded have happened in the 21st century. Arctic spring And the most dramatic changes are observed in the high Arctic, the fastest-warming place on the planet, according to a study in Biology Letters. As the polar sea ice retreats, the growing season gets ever longer – and arrives earlier. The pattern is not consistent: grey willow sticks to its original timetable, and dwarf birch growth has advanced about five days earlier for each decade. But the sedge, almost four weeks ahead of its timetable in a decade, holds the record, according to a study that observed one plot at a field site in West Greenland, 150 miles inland, for 12 years. Read More here
1 March 2017, Thomas Reuters Foundation, Antarctica hits record high temperature at balmy 17.5°C (63.5°F). An Argentine research base near the northern tip of the Antarctic peninsula has set a heat record at a balmy 17.5 degrees Celsius (63.5° Fahrenheit), the U.N. weather agency said on Wednesday. The Experanza base set the high on March 24, 2015, the World Meteorological Organization (WMO) said after reviewing data around Antarctica to set benchmarks to help track future global warming and natural variations. “Verification of maximum and minimum temperatures help us to build up a picture of the weather and climate in one of Earth’s final frontiers,” said Michael Sparrow, a polar expert with the WMO co-sponsored World Climate Research Programme. Antarctica locks up 90 percent of the world’s fresh water as ice and would raise sea levels by about 60 metres (200 ft) if it were all to melt, meaning scientists are concerned to know even about extremes around the fringes. The heat record for the broader Antarctic region, defined as anywhere south of 60 degrees latitude, was 19.8°C (67.6°F) on Jan. 30, 1982 on Signy Island in the South Atlantic, it said. And the warmest temperature recorded on the Antarctic plateau, above 2,500 metres (8,202 feet), was -7.0°C (19.4°F) on Dec. 28, 1980, it said. Wednesday’s WMO report only examined the highs. The lowest temperature set anywhere on the planet was a numbing -89.2°C (-128.6°F) at the Soviet Union’s Vostok station in central Antarctica on July 21, 1983. (Reporting by Alister Doyle; Editing by Louise Ireland) Read More here
28 February 2017, Climate News Network, Inequalities fuel human impacts on climate. For the second time this year, a group of climate scientists has called for a new approach to climate change research to produce a better and more precise idea of how the world will change as global average temperatures rise. The call comes only weeks after a distinguished international team reminded researchers that some details of the planetary climate machine are still unresolved – such as what happens to all the carbon released by fossil fuel combustion, and how rainfall patterns will change in the decades to follow. Neither group is challenging the general climate models, which broadly predict that, unless action is taken, global average temperatures could rise by 4°C and global sea levels by a metre or so. What each wants is more detailed answers. The latest call comes from a team of US and Japanese scientists, who argue in their report in National Science Review journal that the human dimension is missing. What people do over the next decades will feed back into the mechanics of climate change. Missing dimensions The missing dimensions of the human impacts and contribution, they say, are threefold: the economic inequalities that stoke conflict and drive migration; the levels and patterns of consumption of resources that fuel these inequalities; and the numbers of people consuming these resources and demanding energy to improve their lives over the next two generations. For instance, the scientists say, human choices make a difference. The rate of atmospheric concentrations of the greenhouse gases carbon dioxide, methane and nitrous oxide increased 700-fold, 1,000-fold and 300-fold respectively after the “green revolution” of the 1960s, compared with pre-industrial levels. Population growth was a factor. So was economic growth. And this corresponded to a doubling of human impacts every 17 years. “The doubling of this impact is shockingly rapid,” says the study leader, Safa Motesharri, a systems scientist at the University of Maryland’s National Socio-Environmental Synthesis Centre. Read More here