The world imagined a ‘hiatus’ in global warming. Mired in economic crisis, that was simply what it wanted to hear.
In the past 15 years, the world has not warmed in the same scale as it has been doing since 1951, read headlines across the world in the first week of September. There is a “hiatus” in global warming, media reports stated, quoting a draft of an upcoming Intergovernmental Panel on Climate Change (IPCC) report.
A source in the know of the drafting process at the IPCC had leaked the draft of the Summary for Policymakers of the Working Group 1 to Assessment Report 5. This draft contained the assertion on the hiatus.
It read: “Global mean surface temperature trends exhibit substantial decadal variability despite the robust multi-decadal warming since 1901. The rate of warming over the past 15 years (1998-2012; 0.05 °C per decade) is smaller than the trend since 1951 (1951-2012; 0.12°C per decade).”
However, when experts and policymakers met in Stockholm, Sweden, from September 23-26 and released the approved Summary for Policymakers after reviewing the draft line-by-line, there was a technical disclaimer.
It read: “Due to natural variability, trends based on short records are very sensitive to the beginning and end dates and do not in general reflect long-term climate trends. As one example, the rate of warming over the past 15 years, which begins with a strong El Niño, is smaller than the rate calculated since 1951.”
As an explanation, a footnote stated that “trends for 15-year periods starting in 1995, 1996, and 1997 are 0.13, 0.14, and 0.07°C per decade, respectively.” So, when the experts and policymakers added the relevant perspective, the picture looked different.
However, in the three weeks between the leaked draft and when the approved Summary for Policymakers was released, the world was agog with news of a slowdown in global warming.
The good news
The IPCC’s previous document — Assessment Report 4 — was released in 2007, and in the six years, the world’s political economy has changed.
The US went through an economic slowdown and is just recovering, whereas much of Europe is still under economic distress. Pressure to cut down emissions at this stage can affect this recovery process, and thus the news of the hiatus in global warming was a welcome relief.
Even in the emergent economy of India, news of the hiatus provided relief. With the international climate change negotiations working to develop a new instrument to replace the Kyoto Protocol by 2020, the Indian negotiators are under pressure to announce caps to the emission of greenhouse gases that cause global warming.
It was the first time that good news was coming from the IPCC. However, even in the leaked draft, the hiatus looked like an aberration.
The approved Summary confirmed these statements. “Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased,” it stated.
“The human influence on the climate system is clear. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system,” the approved Summary observed. It also added that the number and frequency of extreme weather events have increased.
Myth or reality?
Assessment reports from IPCC have always created intense global interest, discussions and debate. There are two reasons for this. One, the subject of whether global climate is changing is one of intense discussion and the IPCC is the only world body that has the competence to declare scientific opinion on whether this is a myth or reality. Two, IPCC’s assessment reports take many years in preparation and publication, and therefore the world waits to see what the latest in climate science it unravels. The draft gave a peek into what the world body was thinking even before the meeting for the approval process had taken place.
In the excitement of reporting this insight, it was forgotten that the draft was only the first one of a series of documents that the IPCC would be producing over the next year. Working Group 1, which looks at the physical science basis of climate change, is one of the three such groups. Working Group 2 will deal with impacts, adaptation and vulnerability; and Working Group 3 will look into mitigation of climate change. The Synthesis Report of the Assessment Report 5 will be released only in October 2014.
Even if one were to discount conspiracy theories, the premature release of the draft has raised confusion on a subject that is inherently difficult to communicate. There are still many uncertainties related to the science of climate change, and much understanding is still evolving in the scientific world.
IPCC’s reports are meant to provide policymakers with regular assessment of the scientific basis of impact and future risks of climate change and, thereby, decide on options for mitigation and adaptation.
The IPCC is designed as a broad-based body, with 195 countries as members. Its scientists are selected from across the world and from multiple disciplines to draft the reports that give cutting-edge analyses on climate science.
Each of the working groups goes through a multi-stage drafting process for preparing their Summary for Policymakers. This finally concludes in the meeting for the approval process where delegated officials from the IPCC member countries go through the report line-by-line along with the scientists who drafted the report, to validate and finalise the text.
This process was short-circuited when the draft came out in the public domain in early September. The result was that critical information was reported out of context and the world imagined a hiatus in warming that never was.
(The author is regional environment manager with Panos South Asia. The views are personal.)