What Are The Chances Of Getting All These Record Hot Years Without The Extra Greenhouse Gases? The Answer…

authordefault
on

From hot to fractionally less hot, here are the planetโ€™s ten warmest years on record โ€“ 2015, 2014, 2010, 2005, 2007, 2013, 2009, 1998, 2002 andย 2006.

These are the numbers according to NASA and include measurements taken on land and at sea in a record that goes back to the yearย 1880.

Now thatโ€™s a pretty remarkable run of hot years for an era when, according to the rusted-on professional climate science denialists, global warming was supposed to haveย stopped.

But what are the chances of getting a run of โ€œhottest on recordโ€ years like that – 14 of the 16 hottest years all happening since 2000 – without all the extra greenhouse gases that humans have been judiciously stockpiling in the atmosphere andย oceans?

Well, the chances of this happening, climate scientist Professor Michael Mann tells me, areโ€ฆ wait for itโ€ฆ ย one-in-13000. ย Mann, of Penn State University, is the lead author of a new paper published in Natureโ€™s Scientific Reports.ย 

The study takes in data up to 2014, when the chance of that hot streak was one-in-10000.ย  Since the study was submitted, Mann has re-run the numbers to include the new โ€œhottest yearโ€ of 2015, giving us the one-in-13000ย number.

The study looks at how likely (or unlikely) it would be that the planet could serve up a string of hot years without humanย influence.

There are several natural factors that can push global temperatures up or down, such as the amount of energy coming from the sun, the El Nino/La Nina cycle and volcanicย eruptions.

Then of course, thereโ€™s the human influence โ€“ chiefly, the extra greenhouse gases in the atmosphere from burning fossil fuels and chopping downย forests.

Mann and his colleagues took a computer climate model and ran it one million times, creating a series of โ€œsurrogateโ€ climates from 1880 to 2014 allowing for a huge range of different background conditions.ย Then they looked at what those climates would look like if you only removed the greenhouse gases added by humanย activity.

Mann has a longer explanation of his study at Live Science where he discusses some moreย results.

A key motivation for the study was to examine more closely claims made elsewhere that the chances of a record run were even slimmer โ€“ 27 million-to-one according to a report in Salon or 650 million-to-one according to a report from Associated Press.

The main reason why Mannโ€™s numbers are different, is that those reports of much longer odds used a method that did not account for how natural factors โ€“ such as El Nino or volcanic eruptions โ€“ have an impact on surrounding years, rather than just one singleย year.

But Mann explains that even with the method used in his latest study, the chances of a climate without human influences delivering individual years as hot as 1998, 2005, 2010, and 2014 were at least a million toย one.

Doubtsย remain

Many members of the public in westernised English speaking countries are still split on the causes of climate change. ย While increasing numbers accept climate change is real, in the mind of the public thereโ€™s still uncertainty about whether itโ€™s natural orย human-caused.

In Australia, according to a CSIRO survey (with a comparatively large sample of 5000 people), about 39 per cent of Australians agree that climate change is happening but think that itโ€™s causes areย natural.

But does this mean that the chances of that 39 per cent of people being right, are aboutย one-in-13000?

โ€œWell, frankly that would actually be rather charitable,โ€ Mann told me. โ€œThat is the likelihood of that particular statistic being explainable in terms of natural climate variability. But we also looked at other statistics, such as, how easily can we explain โ€œhow warmโ€ 2014 or 2015 was globally. And in each case, we find that the odds are less thanย one-in-a-million.โ€

โ€œSo regardless of how you parse our study – or the collective evidence from other studies for that matter – the evidence is overwhelming that the observed warming of the planet can only be explained by the increase in greenhouse gas concentrations from fossil fuel burning and other humanย activities.โ€

One key contributor to the heat of 2015 was the cycle of ocean temperatures in the tropical Pacific Ocean that can have a global impact on weather patterns and temperatures – a pattern known as Elย Nino.

Professional climate science denialist Patrick Michaels, of the Cato Institute, tried to argue in the Wall Street Journal that the chief cause of the record-breaking temperatures of 2015 was Elย Nino.ย 

Once El Nino drops off, as it likely will in the coming months, Michaels said temperatures would drop away. This is also likely, especially if we get La Nina conditions (generally speaking, having the opposite effect of Elย Nino).

But Michaels does not explain how the global warming trend continues to rise, regardless of whether a year is La Nina or El Nino, as this chart below from NASAย shows.

Michaels also suggested to his readers that people should not trust the temperature data taken by thermometers on the surface of the planet, but should instead rely on temperatures taken byย satellites.ย 

Satellite data shows that 2015 was the third hottest since 1979, when satellite data first becameย available.

Michaels does not explain to his readers that satellite data goes through far greater adjustments than ground-basedย measurements.

Even the scientist who compiles one of the major satellite datasets says that ground-based measurements are better when talking about climateย change.

Some ten scientists at Climate Feedback have fact-checked Michaels column and gave it a scientific credibility rating of โ€œveryย lowโ€.

Or to think about it another way, the chances of Michaels being right are roughly the same as the chance of the world going on a record-breaking heat run without all that extra carbon dioxide in theย atmosphere.

Vanishinglyย slim.

Related Posts

The EU and many member states have set limits for how much manure farmers are allowed to apply in their fields, but crucial oversight is lacking.

The EU and many member states have set limits for how much manure farmers are allowed to apply in their fields, but crucial oversight is lacking.
on

Robert Wilkie was speaking at a conference co-hosted by the group behind the radical Project 2025 agenda.

Robert Wilkie was speaking at a conference co-hosted by the group behind the radical Project 2025 agenda.
on

Scope of corporate influence underscores concerns the technology will be used to prolong demand for planet-heating natural gas.

Scope of corporate influence underscores concerns the technology will be used to prolong demand for planet-heating natural gas.
on

A 1961 oil and gas well is the suspected source of a geyser eruption in the region where Permian wastewater disposal is causing a flurry of earthquakes.

A 1961 oil and gas well is the suspected source of a geyser eruption in the region where Permian wastewater disposal is causing a flurry of earthquakes.