IPCC: Global warming is ‘unequivocal’


Just as it seems readily apparent to most of us when we stick our noses out the door, the warming of the planet’s climate system is “unequivocal.” This is according to the over 1000 scientists of the UN’s Intergovernmental Panel on Climate Change (IPCC), who released the first part of their Fifth Assessment on Sept. 27, in Stockholm. The “Summary for Policymakers” states that each of the last three decades has been successively warmer on Earth’s surface than any preceding decade since 1850, and the human influence on rising temperature due to fossil-fuel combustion is clear.

Using the term “extremely likely,” the scientific body is 95% certain that the warming is anthropogenic, as compared with a 90% “very likely” in its 2007 report, and only 66% “likely” in 2001’s report. This is because the evidence is more firmly established than ever, coming from 9200 peer-reviewed studies, two-thirds of which were published after 2007.

Little has changed since the first assessment of 1990, so we may ask what good this great search for answers on the part of the UN is when nothing has been done to preserve the climate from rampant destruction thus far. In 2012, carbon dioxide emissions were at a record high and rose 1.4% to 31.6 billion tons. In May of this year, seasonal CO2 concentrations in the Northern Hemisphere reached 400 parts per million for the first time. Their rate of increase has accelerated since the last century, and it is now at 2 ppm per year.

Thirty percent of our carbon dioxide emissions have been absorbed by the ocean, causing it to acidify and imperil marine life. The IPCC expects acidification to increase and amplify warming by 0.9F because of the restricted ability of the ocean to take up more carbon. Another important observation the report makes is the eventual thawing of the permafrost down through the top 10 feet, which would release twice as much carbon into the atmosphere. It behooves everyone to pay attention to these and other dangerous feedbacks at work.

Critics often accuse the IPCC of being conservative. This is because of its consensus-based way of drawing conclusions, the undue influence government leaders and environment ministers have on decision making, and the unwillingness of any scientist to be absolutely 100% sure about anything given the gaps in human knowledge. Nonetheless, the IPCC has strengthened its general conclusions: Climate change is indisputably real, caused by humans, and proceeding unabated. The overwhelming evidence is found in warming oceans, vanishing ice masses, rising sea levels, and raging weather extremes due to unrelenting fossil-fuel emissions.

However, some scientists fear that pressure from skeptics may have forced the panel to “low-ball” some of its predictions on sea-level rise and climate sensitivity—the projected effect a doubling of CO2 over pre-industrial levels would have on global temperature if business proceeds as usual. Their new sea-level rise projection is 28 to 97 cm by 2100, which is 50% higher than the old one, but many glaciologists expect a one meter rise (39 inches) by then. Future IPCC temperature ranges from 1.5 to 4.5 Celsius (3-8 F), with a doubling of CO2.

On the other hand, climatologists such as Michael Mann at Penn State believe the low-end effect of doubling CO2 should be 2C. The people of island nations threatened with inundation by rising seas prefer there be no greater than a one-degree rise, but they have little say in the matter since it would appear that the Carbon Barons are hell bent on allowing the situation to play out to the nightmarish doubling scenario.

Whether sea levels and temperatures rise to great extremes, things are already bad enough, and we must stop spewing greenhouse gases into the atmosphere immediately lest they get any worse. Depending upon how grave, some believe the IPCC’s forecasts actually would have an effect on the behavior of the capitalist class and its politicians, who together hold the power of life and death over the rest of us. Based on the experience of the last quarter century, they are undoubtedly unwilling to lift a finger to mitigate and adapt to runaway climate change, and instead have been actively and consistently blocking any efforts to do so. The real question is whether or not the world’s masses will feel moved to rise up and demand fundamental change based on what the IPCC reports.

Over the next year, more of the 4000-page document will be released, with further details and impacts. This is to be followed by another UN climate conference in Paris in 2015, where the extremely hopeful are expecting an agreement among world leaders to be finalized. Given their history, we have our doubts.

A warming pause?

A big issue that was debated hotly before the release of the report was the so-called warming slowdown that has supposedly occurred over the past 15 years despite the continuous rise in greenhouse gas emissions. Industry-funded professional climate-change deniers, trying to cast doubt on the science, had been harping about it for some time. Of course, they gained attention because the media dutifully reports every inane utterance coming out of the skeptics’ mouths, giving the vocal minority equal time on every occasion in the phony name of objectivity, regardless of the truth.

As some defenders of climate science have pointed out, the blip in the meteorological data is really just a statistical mirage that reflects random fluctuations. Although the rate of warming between 1998 and 2012 was half the average rate since 1951 (0.05 C compared with 0.12 C per decade), the globe is still heating.

Using 1998 as the starting point, makes the temperature graph look flatter than it would appear if one began with records from the turn of the century. That particular year, 1998, was the third-hottest on record, when there was an intense El Nino. Beginning instead with 1999 or 2000 yields a more upward-pointing curve because every year after 2000 has been warmer.

From a statistical point of view, it is still the case that the 10 hottest years on record have occurred within the last 14 years, and they occurred during major cooling factors. Because climate is weather averaged out over multiple decades, centuries, and millennia, looking at an isolated 15-year time span can be misleading and not truly reflective of actual trends.

Also to consider are the natural variables that can turn down the temperature dial—volcanic eruptions, the solar cycle, and the El Nino Southern Oscillation (ENSO) when it is in a La Nina phase. Since 1998, there have been a series of medium-sized volcanic eruptions in the Pacific region that have ejected volcanic ash into the atmosphere and reflected incoming solar radiation back out to space.

In addition, an unusually long solar minimum occurred from 2005 to 2010. Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research believes that the transition from the solar maximum to minimum probably contributed as much as a 15% decrease in planetary heat absorption. Yet, despite the volcanism and a reduction in solar insolation, the planet managed to warm.

ENSO is one of the major engines that drives the world’s climate. It consists of an El Nino phase with warm Eastern Pacific Ocean surface waters and the release of heat into the atmosphere, often with a tendency to shed moisture over the ocean. Its counterpart is the La Nina phase, with cold surface waters and the absorption of heat with a tendency to shed moisture over land in some areas.

There have been a cluster of La Ninas in the last decade, (5 LNs compared with 4 ENs). Even so, both El Nino and La Nina years were warmer overall from 1950 to 2010.  Therefore, the noise associated with natural variation does not mean a change in the signal of global warming.  Climatologists believe that the next El Nino could produce a new global mean temperature record because of all the heat the oceans are absorbing.

Ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90% of the heat accumulated between 1971 and 2010, according to the IPCC. This is because the atmosphere holds only 2%, and the land is a poor heat conductor, absorbing slowly. The ocean is thermally stratified. The upper layer—the top 700 meters—holds two-thirds of the warming that has occurred since 1980. Its heat content is two times that of the lower layer located 700 to 2000 meters down.

Over the last decade, the upper layer has warmed more slowly. This apparent slowdown is closely related to the global surface temperature because the temperature of the overlying atmosphere is strongly linked to that of the ocean surface. The reduced warming of the ocean’s upper layer is due not to less heat from above but rather, greater heat loss to below. Thirty percent of the heat is now going into the deep ocean. Cool, deep water rises to the ocean surface, displacing warmer surface water, which in turn gets buried deeper down. This upwelling simultaneously cools the atmosphere.

The ocean is still getting warmer, but the temporary cooling of the Pacific’s surface has constrained global surface temperatures somewhat. This is reflected in ENSO’s La Nina phase. According to a paper by Kevin Trenberth of the National Center for Atmospheric Research, trade winds in the subtropical Pacific have become stronger and altered ocean currents, strengthening subtropical sea water circulation and transporting heat into the deep ocean. This vast body of water—70% of Earth’s surface—continues to grow ever warmer, proving that global heating hasn’t taken a hiatus. Scientists warn that it is only a matter of time until the “missing heat” that’s being sequestered is released to blow up in our faces.

Rapidly disappearing ice masses

 Further proof that conditions are getting warmer is the shocking loss of ice on the planet. The melting of Earth’s cryosphere is accelerating. Last year, summer Arctic sea ice extent reached another record low, and it is not recovering. Because of darkening seawater from lack of reflective snow, the polar ocean is absorbing more sunlight and warming up. The warm seawater makes for slower ice formation in the wintertime. Therefore, there is far less multi-year ice, making it much thinner and reducing not just the extent but the volume of ice as well.

We have radically altered the regime in the Arctic, which in turn, affects weather conditions in the lower latitudes. By heating the Arctic two times faster than elsewhere on the planet, the temperature gradient between it and the temperate zone has been reduced, upsetting the heat balance.

Meandering air streams that encircle the globe draw warm air from the tropics when they swing north and draw cold air from the North Pole when they swing south. These have slowed or ground to a halt in recent summers. These gigantic airwaves can stretch from 2500 to 4000 km (1500-2500 mi.) from crest to crest. An altered or super jet stream can form deep loops, block weather patterns, such as blistering heat waves and withering droughts, and hold them in place for weeks on end. In winter, prolonged, severe cold snaps can occur for the same reason.

In the last two decades, Greenland has lost 140 billion tons of ice each year, and from 2005 to 2010, it lost ice five times faster. This is occurring by two means: (1) Basal melting as warm sea water erodes the ice tongues from underneath, and (2) water boring down into the ice through moulins from vast melt ponds on top and lubricating the ice’s flow to the ocean. In addition to enormous blue lakes forming, the ice is becoming pockmarked with thousands of heat-absorbing dark holes filled with a combination (known as cryokinite) of melt water, desert dust, soot from combustion, and algae. This feeds back on warming.

Similar conditions exist on the Antarctic Peninsula and West Antarctic Ice Sheet (WAIS), with the South Polar region losing 1320 billion metric tons of ice over the last two decades. Together, the losses in the north and south, which are accelerating, have contributed 11.1 mm in sea level rise. Since 1901, sea levels have risen 7.5 inches (19 cm), with significant contributions from alpine glaciers, which are also shrinking at an alarming rate and seriously undermining freshwater supplies for mountain communities and ecosystems.

Antarctica is in a somewhat paradoxical situation. The continent is gaining sea ice but losing land ice, which has accumulated over thousands of years through snowfall. There are two reasons sea ice is gaining in the cold season, which reflects the complexity of the changes humans have wrought. Ozone depletion over the region causes stratospheric cooling that increases winds. By making it stronger, the ozone hole is also affecting the polar vortex that swirls around the bottom of the globe. Converging air currents, blowing in different directions, push the ice around, causing it to pile up in thick ridges. This leaves more open water that can freeze.

Also, the Southern Ocean is freshening. There has been an increase in snow and rainfall due to greater volumes of water vapor in a warming atmosphere. In addition, melting ice from the peninsula and WAIS provide move freshwater that freezes more easily than salty. Fresher seawater, being less saline, means there is more stratification and less mixing between the warm and cold layers, and thus less melting of sea ice. Eighty percent of the sea ice growth can be explained by changing prevailing winds and 20% by ocean circulation. The southern sea ice increase has been at a rate of 1% per decade on average over the past 30 years. This pales in comparison to the 15.5% loss per decade in the north.

While the interior of East Antarctica’s ice sheet—considered much more stable than the peninsula or WAIS—grew some between 1992 and 2011, it has been discovered that persistent wind scour on the surface actually erodes and sublimates the snow, reducing its accumulation. Because of that, researchers have found that surface-mass-balance has been overestimated by 11 to 36.5 gigatons per year. So the East Antarctic ice mass is not growing as much as had been previously assumed. This removes further ammunition from skeptics who claim that Earth’s ice masses have always had ups and downs and always will, when the actual trend is toward loss rather than gain.

Another dire consequence of warming temperatures at the poles is the thawing of permafrost both on land and the continental shelf. Vast plumes of methane (CH4) have been found by a Russian research team in the Siberian Arctic. As frozen seafloor sediments become unstabilized by warming sea water, they are releasing hundreds of methane fountains from the seabed, some more than a kilometer across. CH4 eventually oxidizes to CO2 and would ordinarily do so in the water column in the deeper ocean, but in this case, because of the shallow depths over the continental shelf, there is no time for the methane to oxidize before reaching the surface. Therefore, it is outgassing straight into the atmosphere, with 23 times more global heating potential. This is an extremely powerful feedback that could get out of control very quickly.

That is why working people the world over must take matters into their own hands and demand a system change, not climate change!

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[Editor’s note: We reprint this article by the Committee for the Abolition of Illegitimate Debt (CADTM). In 1989, the Bastille Appeal was launched, inviting popular movements throughout the world to unite in demanding the immediate and unconditional cancellation of the debt of the so-called developing countries. This crushing debt, along with neo-liberal macro-economic reforms imposed on the global South, has led to an explosion of worldwide inequality, mass poverty, flagrant injustice and the destruction of the environment.


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