Back in 2009, at the United Nations (UN) Framework Convention on Climate Change, nations around the world drew a hypothetical line in the sand, pledging to do everything in their power to prevent the world annual average temperature from warming an additional two degrees Celsius (3.6 °F) - known as the Copenhagen Accord. Now, nearly six years later, experts are saying that even this lofty goal won't be enough to save many nations.

That's at least according to a commentary report recently issued by the Intergovernmental Panel on Climate Change (IPCC) and published in the open access journal Climate Change Responses.

The report details the nitty-gritty of a two-day discussion at the 2014 Lima Conference of the Parties (COP) on the likely consequences of accepting an average global warming target of two degrees Celsius versus something even less.

"The consensus that transpired during this session was that a 2°C danger level seemed utterly inadequate given the already observed impacts on ecosystems, food, livelihoods, and sustainable development," report author Petra Tschakert, from The Pennsylvania State University, said in an emailed statement.

"A low temperature target is the best bet to prevent severe, pervasive, and potentially irreversible impacts while allowing ecosystems to adapt naturally, ensuring food production and security, and enabling economic development to proceed in a sustainable manner," she added. (Scroll to read on...)

In the commentary, Tschakert argues that the Copenhagen Accord was based upon severely outdated material that stretches back to the 1970s - when experts had a far weaker understanding of the globe's carbon cycle and the effects of climate change.

She pressed that in light of new climate data collected over the last several decades, there is now strong evidence that limiting global warming to two degrees won't be enough. And that's exactly what over 70 percent of the parties involved in recent climate talks - including 100 low- and middle-income countries and small island states - have been arguing.

It should be noted that their complaints are not exactly being ignored, as the two percent limit is already under review. However, many of these states are calling for a hard 1.5 degrees limit instead - a decision that could cost nations already committed to the cause billions of dollars in emissions cuts and reformation.

Many climatologists, however, press a different point.

"Using a figure for average global warming may indeed be the most convenient and compelling means to discuss the severity of climate change impacts, but not only does it inadequately capture the complexity of the climate system, it poorly reflects locally experienced temperature increases and the extreme and large variation across regions," Tschakert explained. "No single person or any species faces a global average." (Scroll to read on...)

The report details that many of these smaller tropical nations are calling for a 1.5-degree limit because it could keep sea level rise below one meter - which could save half of the world's corals and leave some essential Arctic ice intact.

However, past research conducted by the Global Carbon Project has already shown that means to keep even that two degrees limit are slipping away.

A recent report from researchers at the University of California and the Scripps Institution of Oceanography shares that sentiment, saying that "owing to continued failures to mitigate emissions globally, rising emissions are on track to blow through this limit eventually."

The authors of the report recommend that nations abandon such a vague and "arbitrary" goal as limiting warming, and instead focus their efforts on mitigating expected consequences of that warming - such as radical changes to water quality and availability.

Tschakert's commentary seems to have a similar take-home message.

"The crux of the matter is no longer about the scientific validity of one temperature target over another," she said. "It is about acknowledging that negative impacts of climate change under a 0.8°C temperature increase are already widespread, across the globe, and that danger, risk, and harm would be utterly unacceptable in a 2°C warmer world, largely for 'them' - the mollusks, and coral reefs, and the poor and marginalized populations... even if this danger hasn't quite hit home yet for 'us'."

Still, how the world could respond to climate change, if not through some kind of international standard like the Copenhagen Accord, remains to be seen.

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