Thursday, 29 October 2015

1.2C -1.2C warmer than baseline - and beyond

A World Where Heat Haunts Us — 2015 May See Worst El Nino Ever as Global Temperatures Rocket Past 

1 C Mark

28 October, 2015

It’s a world that’s adding more than 50 billion tons of carbon dioxide equivalent gasses to the atmosphere every single year. It’s a year where, according to Ralph Keeling, we are likely to never see atmospheric CO2 levels in the 300-399 parts per million range ever again in our lifetimes. And it’s a time when global temperatures are at their hottest ever recorded by human instruments — likely to hit a very dangerous range between  1 and 1.2 C hotter than 1880s averages during 2015 and 2016.

Tracking the 2 C limit
(As of August 2015, 12 month averages were in the range of 0.926 C below the so called ‘safe limit’ of 2 C warming since 1880. What may become the worst El Nino on record may combine with a growing overburden of human hothouse gasses to push global temperatures to within between 0.9 to 0.8 C of the +2 C limit during 2015 and 2016. Image source:Skeptical Science.)

This is the context we all live in today. A world that’s sweltering in a toxic atmospheric stew of human hothouse gas emissions. But underneath that heat-amplifying context, the traditional ebb and flow of natural variability still has its own set of influences. And this year,the warm side of natural variability — in what may become the strongest El Nino ever recorded — is coming back to haunt us with a vengeance.

Previous Worst El Nino On Record

Forget the so called ‘2 C safe limit’ set by international government bodies for a moment and think about all the extreme weather, the droughts, the wildfires, the loss of access to water, the increasing rates of sea level rise, the increasing rates of glacial destabilization, and the rapid declines in ocean health that have all happened since 1997 — the previous worst El Nino year on record.

Back then, atmospheric CO2 levels had just breached the 360 parts per million mark. And, in that year a powerful El Nino — the peak of the natural variability hot side — shoved global temperatures into the range of 0.85 C above 1880s averages. It was the strongest El Nino ever recorded in the modern age. And it was occurring in a climate in which greenhouse gas concentrations were the highest seen in about 1 million years. It was a confluence of forces that propelled the Earth toward a new, more violent climate state. One not seen for millennia and one that was increasingly outside the ice-age and inter-glacial norm in which human beings evolved and learned to flourish.
Over the 2000s and early 2010s, despite a swing in atmospheric natural variability back toward ‘cool,’ negative PDO, conditions, global temperatures continued to climb. Greenhouse gasses were building up in the atmosphere at record rates. Rates about 6 times faster than during the Permian hothouse extinction event that wiped out 75 percent of life on land and more than 90 percent of life in the oceans. As a result, new global high temperature records were hit in 2005 and 2010 even as the oceans drew in a massive amount of atmospheric heat. Heat that, according to Dr, Kevin Trenberth, would again back up into the atmosphere as the natural limits for ocean heat uptake were eventually reached.

By 2014, as CO2 levels climbed into the 400 parts per million range and atmospheric heat uptake built, it appeared those limits had, indeed, been overwhelmed. Heat in the upper Equatorial Pacific Ocean began to spike as massive and powerful Kelvin Waves rippled across the world’s largest ocean, setting the stage for a new, monster El Nino. An El Nino that appeared to be building toward an event that would rival even the record 1997 El Nino.
2015 El Nino May Become Worst Ever Over Next Few Weeks

At first, the climb toward a record El Nino was slow. Even as ocean heat hit El Nino thresholds during the summer of 2014, the atmospheric response lagged — resulting in a steady climb into weak El Nino conditions through early 2015. Despite this slow advance, underlying conditions hinted at an extreme amount of available heat. The Oceanic hot pool was widespread and very intense — generating a heat bleed that pushed global atmospheric temperatures to new records for the year of 2014 and intensifying into 2015. By late Fall of 2015, atmospheric temperatures had rocketed into a range near 1.1 C above 1880s averages. But the top of the temperature spike was likely still to come.
For throughout October El Nino continued to strengthen, reaching a new height of 2.5 C above average in the benchmark Nino 3.4 zone last week. This temperature spike is comparable to a record in the same region at 2.7 C above average for peak weekly values during the 1997 El Nino.

(Setting up for a strongest El Nino on record? Global climate measures now show the Equatorial Pacific is becoming hot enough to challenge ocean surface temperature records previously set by the 1997 El Nino. If new record values are set, they could occur by early to mid November. Ocean temperature anomaly image source: Earth Nullschool.)

Unfortunately, heat continues to build in this benchmark region of the Pacific. A rudimentary grid analysis of ocean models and readings for this week indicate daily measures in the range of 2.5 to 2.8 C above average. Daily measures that show a consistent warming trend. A trend that, if it continues, is likely to push Nino 3.4 temperatures into a range comparable with or exceeding the 1997 El Nino high temperature mark by early-to-mid November.
In other words, the 2015 Monster El Nino event appears to be setting up to tie or beat the record-shattering 1997 El Nino over the next few weeks.
Max Temperature Spike is Coming

Regardless of whether we see the 1997 record shattered, it is likely that heat bleeding off the current Monster El Nino will continue to amplify atmospheric temperatures on through early Spring of 2016. What this means is that we haven’t seen the hottest global temperatures out of this event yet. Preliminary estimates for October are coming in the range of 1.1 to 1.2 C above 1880s values. 
Meanwhile, a peak in atmospheric temperature is likely to occur within 1-4 months after El Nino itself peaks. So though 2015 has been a record breaker so far, we may see global heat intensifying through to 2016 with new monthly temperatures testing never before seen ranges. This added heat provided from a Monster El Nino makes it a distinct possibility that we will see three back-to-back record hot years — 2014, 2015, and 2016.

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