Global warming: Humans the ‘dominant cause’

Picture: PA
Picture: PA
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SCIENTISTS are 95 per cent certain humans are the “dominant cause” of global warming since 1950, according to a landmark report.

The study, by the United Nations Intergovernmental Panel on Climate Change (IPCC), says on the ground, in the air and in the oceans global warming is “unequivocal” and is likely to speed up if action is not taken to reduce man’s impact on the environment.

It also says that weather will continue to move to extremes and while many parts of the world heat up, the UK is likely to get colder.

The three-part study, the first section of which is to be published on Monday, is considered the most comprehensive statement on our understanding of the mechanics of a warming planet.

The IPCC received the Nobel Peace Prize in 2007, after its previous report, “for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change”.

In its new report, the panel warns that continued emissions of greenhouse gases will cause further warming and changes in all aspects of the climate system. And the experts warn that to contain these changes will require “substantial and sustained reductions of greenhouse gas emissions”.

Qin Dahe, co-chairman of the IPCC working group which produced the report, said: “Our assessment of the science finds the atmosphere and ocean have warmed, the amount of snow and ice has diminished, the global mean sea level has risen and concentrations of greenhouse gases have increased.”

The report found surface temperatures in the past 30 years have been progressively warmer than in any decade since 1850, and that 1983 to 2012 was probably the warmest three decades in the northern hemisphere over the last 1,400 years.

It reported that fossil fuels emissions were the primary reason for climate change followed by human-induced land use, land-use change and forestry activities.

Results showed sea-level rises since the mid-19th century have been greater than the average over the past two millennia, with a 19cm increase between 1901 and 2010. And the scientists say that sea level rise will proceed at a faster rate than we have experienced over the past 40 years.

Waters are expected to rise, by between 26cm and 82cm depending on the greenhouse emissions this century.

The experts conclude that most aspects of climate change would continue for many centuries to come, even if C02 emissions were halted.

The report sparked renewed calls for the Scottish Government to ensure its ambitious climate change goals are met, after the first targets on cutting carbon emissions were missed.

Green MSP Patrick Harvie said: “The tone of this report is clear – the need for action to reduce emissions has never been more urgent. If we are remotely serious about living up to our ambitions we need to see radical policy shifts.”

And Dr Richard Dixon, director of Friends of the Earth Scotland, said: “The world’s politicians can’t continue to stand idly by while the world goes spinning towards a climate catastrophe. Tough action is urgently needed to end the planet’s dangerous fossil fuel fixation and to develop the huge job-creating potential of renewable power – with countries like Scotland taking the lead.”

He called for more investment in insulating homes, a shift in focus from cars to public transport, walking and cycling and continuing transformation of the electricity sector.”

Scottish environment and climate change minister Paul Wheelhouse said: “The case for global action is compelling, which is why Scotland has set world-leading greenhouse gas emission reduction targets, and has detailed plans on how to meet our target to reduce Scotland’s emissions by 42 per cent by 2020.”

Scotland’s emissions reduction of 29.6 per cent is the largest in the EU, but Mr Wheelhouse agreed more must be done. “We need the rest of the UK, our European neighbours and indeed all countries to share our ambition.”

Since 1950, the experts say, human behaviour is clearly responsible for more than half of the observed increase in temperatures. The most controversial part of the report – which is based on a review of 9,000 scientific papers – is the slowing of the rate of climate change since 1998.

Since the 1950s the world’s temperature has risen by 0.12C per decade – but since 1998 it has slowed to 0.05C per decade. This has been seized on by many climate sceptics as evidence that climate change is at the least stalling, if it has not stopped. But the report argues climate change has to be assessed over decades and not short periods of time, meaning 15 year blips are not unusual.

The study says: “Trends based on short records are very sensitive to the beginning and end dates and do not in general reflect long-term climate trends.”

This is accompanied by evidence from the Met Office which says the ten warmest years on record have occurred since 1998.

But the report sparked an angry backlash from sceptics around the world. “No one should trust the report,” said Professor Bob Carter chief science adviser of the International Climate Science Coalition, a group of scientists, economists and energy and policy experts who are working to promote better understanding of climate science and policy worldwide.

“The IPCC has a history of malfeasance that even includes rewording recommendations of expert science advisers to fit the alarmist agenda of participating governments.”

Dr Tim Ball, former climatology professor at the University of Winnipeg, Canada, said: “Sadly, this IPCC report will give governments unjustified confidence to impose carbon dioxide regulations so severe that the world’s most important energy sources, hydrocarbon fuels, will be phased back, sentencing billions of the world’s most vulnerable people to the misery of energy poverty.”

The aim of the IPCC, chaired Rajendra K Pacahauri is “to provide the world with a clear scientific view on the current state of knowledge in climate change and its potential environmental and socio-economic impacts”.

It has issued four previous assessments on the state of the climate, commissioned by the governments of 195 countries. The reports have been used to inform climate policies in these countries.

Analysis: ‘People still care, but it is slipping down their agenda’

The Intergovernmental Panel on Climate Change has said that it is now 95 per cent certain that humans have been the dominant cause of global climate change since the 1950s.

But do people still care about climate change? I think they do, but it is going down people’s agenda because they have got more pressing concerns, such as jobs and the pressures on household economies.

Politicians scrambled to embrace the topic in the 2000s when western economies were growing strongly, markets had access to plenty of capital and a wholesale “transition” to low-carbon technologies seemed all but inevitable. But the financial crisis that began in 2008 diverted attention and resources away.

Those tasked with making the transition happen came up against major technical, commercial, investment and political and public acceptability challenges.

Politicians and the public now have less time to concern themselves with things that are long term. There is also the problem of what people can actually do about it.

People will say: “Well, I recycle”, which is good but it’s not going to tackle climate change. Unless we deprive ourselves of things which we have got used to having and doing, such as hopping on a cheap flight to Spain for a holiday, it won’t change.

Transport accounts for a third of all carbon emissions so we really have to look at that. Politicians are very aware that restricting people’s personal use of cars will not be popular. The Scottish Government targets on reducing carbon emissions will be incredibly difficult and incredibly expensive to achieve.

There is also the effect of the so-called “pause” in global mean temperature change over the past 15 years despite vast increases in atmospheric CO2 emissions over this period.

Climate sceptics have picked up on the “pause” as a major problem for the dominant consensus and a reason for doubting the climate models and theories that go into them.

The IPCC made some valid points in response, but the sceptics have been able to play to this new mood of uncertainty and political disunity in the UK with notable success.

Opinion polls have shown that climate change isn’t as important to the British public as it was a few years ago and there has been a notable increase in those distrustful of the consensus position.

Our politicians are too eager to draw upon the IPCC when it makes them look progressive, but there is insufficient follow-up in terms of creating policies and regulations that can reduce carbon emissions and give climate policies an “up-side” for society – improving lives, communities and opportunities.

To tackle climate change effectively we need better politics supported, not led by, science.

• Dr Simon Shackley, is a climate change specialist at the University of Edinburgh