Ramon Pichs Madruga, Co-Chairman of the IPCC Working Group III, Ottmar Edenhofer, Co-Chairman of the IPCC Working Group III, and

Ramon Pichs Madruga, Co-Chairman of the Intergovernmental Panel on Climate Change (IPCC) Working Group III, Ottmar Edenhofer, Co-Chairman of the IPCC Working Group III, and Rejendra K. Pachauri, Chairman of the IPCC, from left, pose prior to a press conference yesterday. Photo: Michael Sohn, AP

Urgent action by governments around the world is required to prevent the average global temperature from reaching a disastrous 4.8°C (8.6°F) by the end of the century, according to a new report, endorsed by governments, from the U.N.'s Intergovernmental Panel on Climate Change (IPCC) after a one week meeting in Berlin.

The body said that the cost would be "relatively modest," but only if the world acts quickly. The world has already agreed to limit temperature rises to a maximum of 2°C (3.6°F) above pre-industrial times, but greenhouse gases already emitted into the atmosphere, together with actions taken by governments will see the average temperature surpass this, meaning that much stronger action is required now.

The report, Mitigation of Climate Change, (the Working Group III contribution to the 5th Assessment Report by the Intergovernmental Panel Climate Change) is intended to provide a scientific a basis for negotiations currently ongoing which are intended to result in a binding, global legal agreement at the end of next year, in which all countries will sign up to take the required measures.

Failure to take the required action will result in even more extreme weather events such as floods, droughts, heat waves and rising sea levels that are the signature of global warming now widely accepted as being caused by humankind's burning of fossil fuels.

Coincident with this, a consortium of international corporations with a collective turnover of at least $90bn, led by the Prince of Wales's Corporate Leaders Group, has issued a call for governments to put in place policies to prevent the cumulative emission of over a trillion tonnes of carbon.

The Trillion Tonne Communiqué, so far signed by 70 companies from 5 continents - including major multinationals like Acciona, Adidas, CalSTRS, EDF Energy, ING, Mars, Shell, TetraPak, and Unilever - calls for a ‘rapid and focused response’ to the threat of rising global carbon emissions, and the ‘disruptive climate impacts’ inevitably associated with them. It calls on governments to:

  • Set a timeline for achieving net zero emissions before the end of the century
  • Design a credible strategy to transform the energy system
  • Create a plan to manage reliance on fossil fuels, especially coal.

What we must do

The IPCC's scenarios show world emissions of greenhouse gases need to peak soon and tumble by between 40 and 70% from 2010 levels by 2050, and then to almost zero by 2100, to keep rises below 2°C. They foresee gas replacing the more polluting coal as an interim measure towards the complete phase-out of fossil fuels.

Most importantly, low-carbon energy generation, which accounted for 17% of world energy supplies in 2010, has to triple or quadruple by 2050, displacing conventional fossil fuels as the top source of energy. Low-carbon energy could include coal-, natural gas or oil-fired power plants if they were to use carbon capture and storage (CCS) to bury greenhouse gases underground, but the technology, has proven to be more costly and difficult to implement than was envisaged by some a few years ago.

Activists of the international environmentalist organization Greenpeace pose with posters in front of the Brandenburg Gate in Be

To underscore this Greenpeace Germany activists scaled Berlin's iconic Brandenburg Gate yesterday urging governments and businesses to deliver “Power to the People – Clean Energy Now” (Photo: Michael Sohn, AP).

In the medium term, if we failed to cut greenhouse gas emissions through increased energy efficiency and low carbon generation, "ambitious mitigation may even require removing carbon dioxide from the atmosphere," the IPCC said.

One method of doing so will be to burn wood, crops and other biomass to generate electricity, to capture the greenhouse gases emitted during combustion and to bury them underground to reverse the process begun with the industrial revolution. But this is a risky and unproven technology and one that is likely to prove expensive and impractical; one unwanted consequence could be an increase in food prices.

The IPCC says that a simpler method to remove these gases is to plant trees and allow them to soak up carbon dioxide from the atmosphere. The report does not mention geo-engineering options, which are currently also wildly improbable and unrealistic.

Leaders welcome the report

World leaders welcomed the IPCC report. US secretary of state John Kerry said it "makes very clear we face an issue of global willpower, not capacity".

Eliot Whittington, Deputy Director of The Prince of Wales’s Corporate Leaders Group, said that the report contained "stark home truths about the scale of the challenge and the progress we’re making to date", adding that it "is the [report] that many businesses have been waiting most eagerly to read – the latest scientific analysis of the solutions that we can employ to limit the stock of atmospheric greenhouse gases and the consequent climate change."

European Union Climate Commissioner Connie Hedegaard said: "The report is clear: there really is no plan B for climate change. There is only plan A: collective action to reduce emissions now."

The IPCC report is the third and final in a United Nations series that updates the science of climate change for the first time since 2007. A summary of findings will be issued in October.

Early action is cheaper

The report underscores the findings of Lord Nicholas Stern's Review, commissioned for the UK government and now eight years old, that it is cheaper to take action earlier rather than later to prevent climate change becoming too disastrous. 

He said last week that the situation now is worse than it was when his Review appeared. “Emissions have been increasing faster than we anticipated then, and some of the effects are coming through faster than we thought,” said Lord Stern, citing shrinking Arctic ice and rapid acidification of the oceans as two such changes under way.

He said that his conclusion that global economic output could dip by up to 20% as a result of unchecked climate change was likely to be "an underestimate". 

While praising recent reports by the Intergovernmental Panel on Climate Change (IPCC), Lord Stern said models underplay risks – and likely costs – by excluding so-called tipping-point events such as the release of enormous amounts of the potent greenhouse gas methane if Arctic permafrost melts. “These are not formally in most of the climate scientific models,” Lord Stern said.