UN scientists in overwhelming 'wake up' call on global warming
27.09.13 @ 23:01
BRUSSELS - Leading scientists backed by 110 governments say the dumping of greenhouse gas emissions through human activity is directly linked to climate change.
“It is extremely likely that changes in our climate system for the past half century are due to human influence,” Michel Jarraud, secretary-general of the World Meteorological Organization, told reporters in Stockholm on Friday (27 September).
Jarraud’s warning for world leaders to act on climate followed the release of a summary of a major report by the United Nation’s Intergovernmental Panel on Climate Change (IPCC).
Entitled "Climate Change 2013: The Physical Science Basis," the document is part of the IPCC’s fifth assessment report, due out sometime in November 2014.
The 36-page condensed version aimed at policy makers was presented by the IPCC on Friday, with the full 2,014-page version to be released next week.
The scientists conclude, with an at least 95 percent amount of certainty, that humans are the dominant cause of global warming since the mid-20th century.
They say the between 800 and 880 gigatonnes of carbon being pumped into the atmosphere will push temperature levels beyond 2 degrees Celsius, exposing future generations to dangerous consequences.
An estimated 530 gigatonnes of carbon was already emitted by 2011.
IPCC is calling upon leaders and industry to make drastic cuts to emissions in a wider effort to ensure a better future for generations to come.
Achim Steiner, executive director of the United Nations Environment Programme, speaking via video feed from Nairobi, said “for humanity to take decisions, perfect knowledge can never be the condition.”
“You may not know everything, but you know enough in order to be able to assess the risks of acting and the many opportunities that actions provide,” he added.
Around 250 authors worked on the report in the past several years, using the latest advances in science and technology.
They cite over 9,200 peer-reviewed articles, two-thirds of which were written after 2007.
Some 1,000 people, from government representatives to experts, combed through the text to ensure accuracy, tabling over 54,000 review comments, which were then analysed by the IPCC team.
“This is yet another wakeup call: those who deny the science or choose excuses over action are playing with fire,” said US secretary of state John Kerry in a statement after its release.
He added: “If ever there were an issue that demanded greater co-operation, partnership, and committed diplomacy, this is it.
The conclusions cited in the 18 headline summaries make sober reading.
The first headline says that the climate changes seen since the 1950s are unprecedented compared to the millennia which came before.
Atmospheric concentration of carbon dioxide, methane, and nitrous oxide has increased to levels never before seen in the last 800,000 years.
It states carbon dioxide concentrations have increased by 40 percent since pre-industrial times, primarily from fossil fuel emissions and secondarily from net land use change emissions.
The ocean has absorbed about 30 percent of the emitted anthropogenic carbon dioxide, causing ocean acidification.
The last 10 years are also the warmest on record, with more temperature records broken than any other previous decade.
The last 30 years in the northern hemisphere are the warmest since the 1400s.
It notes that the Earth’s surface temperature, rising ocean levels, melting ice caps, and extreme weather patterns like heat waves, droughts and floods are all linked to human activity.
The report says the temperature highs would have been even greater had not it been for cooling events, attributed to volcanic activity and deep oceans, that absorb some of the extra heat.
The group also put together an atlas of regional and global climate change projections to help people analyse the impact climate change will have in the next 50 to 100 years.
“We hope this [atlas] will be useful to a wide range of the public,” said Thomas Stocker, an IPCC co-chair of the working group.
Climate skeptics, for their part, say the heat patterns across the globe for the past 15 years have remained steady.
They claim the so-called "warming hiatus" discredits the science that says humans engineered climate change.