Global Carbon Dioxide Levels Break 400 ppm Milestone
May 10, 2015 Adam Vaughan / The Guardian
Concentrations of CO2 greenhouse gas in the atmosphere reached record global average in March, figures show, in a stark signal ahead of Paris climate talks. Researchers say heatwaves that previously occurred once every three years are now happening every 200 days thanks to global warming.
(November 17, 2014) -- An ultra-high-resolution NASA computer model has given scientists a stunning new look at how carbon dioxide in the atmosphere travels around the globe.
Global Carbon Dioxide Levels Break 400ppm Milestone Adam Vaughan / The Guardian
LONDON (May 6, 2015) -- Record carbon dioxide (CO2) concentrations in the atmosphere were reported worldwide in March, in what scientists said marked a significant milestone for global warming.
Figures released by the US science agency Noaa on Wednesday show that for the first time since records began, the parts per million (ppm) of CO2 in the atmosphere were over 400 globally for a month.
The measure is the key indicator of the amount of planet-warming gases man is putting into the atmosphere at record rates, and the current concentrations are unprecedented in millions of years.
The new global record follows the breaking of the 400ppm CO2 threshold in some local areas in 2012 and 2013, and comes nearly three decades after what is considered the 'safe' level of 350ppm was passed.
"Reaching 400ppm as a global average is a significant milestone," said Pieter Tans, lead scientist on Noaa's greenhouse gas network.
"This marks the fact that humans burning fossil fuels have caused global carbon dioxide concentrations to rise more than 120ppm since pre-industrial times," added Tans. "Half of that rise has occurred since 1980."
World leaders are due to meet in Paris for a UN climate summit later this year in an attempt to reach agreement on cutting countries' carbon emissions to avoid dangerous global warming.
Dr Ed Hawkins, a climate scientist at the University of Reading told the Guardian: "This event is a milestone on a road to unprecedented climate change for the human race. The last time the Earth had this much carbon dioxide in the atmosphere was more than a million years ago, when modern humans hadn't even evolved yet.
"Reaching 400ppm doesn't mean much in itself, but the steady increase in atmospheric greenhouse gases should serve as a stark reminder of the task facing politicians as they sit down in Paris later this year."
Greenhouse gas emissions from power plants stalled for the first time last year without the influence of a strict economic recession, according to the International Energy Agency, an influential thinktank.
Nick Nuttall, a spokesman for the UN Framework Convention on Climate Change (UNFCCC) which oversees the international climate negotiations, said: "These numbers underline the urgency of nations delivering a decisive new universal agreement in Paris in December -- one that marks a serious and significant departure from the past.
"The agreement and the decisions surrounding it needs to be a long term development plan providing the policies, pathways and finance for triggering a peaking of global emissions in 10 years' time followed by a deep, decarbonisation of the global economy by the second half of the century."
But even if manmade emissions were dramatically cut much deeper than most countries are planning, the concentrations of CO2 in the atmosphere would only stabilise, not fall, scientists said.
James Butler, director of Noaa's global monitoring division, said: "Elimination of about 80% of fossil fuel emissions would essentially stop the rise in carbon dioxide in the atmosphere, but concentrations of carbon dioxide would not start decreasing until even further reductions are made and then it would only do so slowly."
Concentrations of CO2 were at 400.83ppm in March compared to 398.10ppm in March 2014, the preliminary Noaa data showed. They are are expected to stay above 400pm during May, when levels peak because of CO2 being taken up by plants growing in the northern hemisphere.
Noaa used air samples taken from 40 sites worldwide, and analysed them at its centre in Boulder, Colorado. The agency added that the average growth rate in concentrations was 2.25ppm per year from 2012-2014, the highest ever recorded for three consecutive years.
'It's Gone' -- Snowpack Crucial for West's Water Melts Early NBC News
(May 8, 2015) -- The snowpack that is crucial for the western US supplies of water for farming, drinking and recreation has melted early, spelling further drought problems for California.
"Across most of the West, snowpack isn't just low - it's gone," Hydrologist David Garen of the United States Department of Agriculture's Natural Resources Conservation Service (NRCS) said. "With some exceptions, this year's snowmelt streamflow has already occurred."
After months of unusually warm temperatures, the snowpack at many off the USDA's stations in much of the western US is at or near the lowest on record, Garen said in a statement from the USDA.
"We still have some snowpack in northern Colorado, western Montana and southern Wyoming," said Garen. "In addition, snowmelt from Canada will flow into the Columbia River."
California is struggling with a four-year drought that has forced Gov. Jerry Brown to impose historic restrictions on water use. The state's water regulators on Tuesday leveled sweeping restrictions on water use state-wide, after the state fell short on targets for reducing water use.
The rules force cities to limit watering on public property, encourage homeowners to let their lawns die and impose mandatory water-savings targets for the hundreds of local agencies and cities that supply water to California customers. Extreme Weather Already on Increase
Due to Climate Change, Study Finds Karl Mathiesen / The Guardian
LONDON (April 27, 2015) -- Extreme heatwaves and heavy rain storms are already happening with increasing regularity worldwide because of manmade climate change, according to new research.
Global warming over the last century means heat extremes that previously only occurred once every 1,000 days are happening four to five times more often, the study published in Nature Climate Change said.
It found that one in five extreme rain events experienced globally are a result of the 0.85C global rise in temperatre since the Industrial Revolution, as power plants, factories and cars continue to pump out greenhouse gas emissions.
"A lot of us and our colleagues were surprised by how high these numbers are already now in the present day climate," said Dr Erich Markus Fischer from the Swiss Federal Institute of Technology.
What represents an extreme day varies depending on the background climate. In the south-east of England, for example, temperatures used to reach 33.2C once every 1,000 days, but are now happening as much as once every 200 days.
Future warming will bring a more volatile, dangerous world, even if the world manages to keep temperature rises within a 2C limit to which governments have committed, Fischer's research found. On average, any given place on Earth will experience 60% more extreme rain events and 27 extremely hot days.
Numbers of extreme weather events spiral even higher at a rise of 3C, a level of warming that the world is on track to exceed with current levels of manmade global greenhouse gas emissions.
Drawing links between specific weather events and climate change can erode the sense that climate change is something that will happen in the future, rather than causing havoc in the present. But the science, called attribution, has proved complicated.
Peter Stott, a scientist at the UK's Met Office Hadley Centre, said the new study was an important step in attribution science.
"What has been lacking up to now is a robust calculation of how much more likely extreme temperatures and rainfall have become worldwide."
The study shows warming of the atmosphere increases the number of times temperatures reach extreme levels and evaporates more water from the oceans. It is from this hotter, wetter background that extreme weather events emerge.
Longer events, such as heat waves and prolonged rainy periods, will also occur more often.
"When we talk about 15-day precipitation or 15-day heat waves rather than one-day cases, one very robust finding is the longer the period the higher the fraction that is attributable to warming," said Fischer.
The study also found that the effects of warming will vary around the world. Weather events at the equator will become more extreme with 2C of warming, meaning tropical countries already dealing with frail infrastructure and poverty will experience more than 50 times as many extremely hot days and 2.5 times as many rainy ones.
But some already dry regions including the parts of the Mediterranean, North Africa, Chile, the Middle East and Australia will experience less heavy rain days.
"In the UK, for a one-in-a-thousand day, which is one in three years, we would probably be well adapted to that," said Stott. "But I think we've shown that we are vulnerable to more extreme situations -- those that happen once in a century. For example the wet winter we had in 2013-14. Or indeed the heatwave we had back in 2003 when many vulnerable, eldery people died. But in the tropics, in parts of the developing world, they are extremely vulnerable to one-in-three year events."
Saleemul Huq, a Bangladeshi scientist who has been involved in the UN climate negotiations, said the developing world was already struggling to cope with extreme events.
"The increased probability of high rainfall events will enhance the adverse impacts of these events in many parts of the world, particularly for vulnerable communities. For example short bursts of intense rainfall in Dhaka already cause huge traffic jams and misery for its citizens," he said.