Tweet of the week - Another record year?

A new year begins, so it is almost time to see how 2014 measures with previous years - did the warming trend continue?

Will 2014 be the warmest year on record? Watch this space #climate2014 pic.twitter.com/6kF4rZDs7M
— WMO | OMM (@WMOnews) January 2, 2015

To the surprise of all (... not really), the Earth continued warming. At the beginning of December, the WMO issued a press release that stated that, if 2014 continued the same trend in November and December as what was observed from January to October, it would be among the hottest - if not the hottest - year on record. Global air average temperature (Jan-Oct) was 0.57°C higher than the 1961-1990 reference period. Over land average air temperature was 0.86°C higher.

 

Average temperature over land will continue warming faster that over the sea. Figure 1 shows the change in surface temperature per degree Celsius of global mean change, as projected for the 21st century (IPCC, 2013).

Fig. 1: mean surface temperature increase per °C of global
mean temperature increase. Source: IPCC, AR5

 

This means that the average global temperature is just that, an average. A warming in 2°C is not distributed equally around the globe, but there can be cooler areas and other areas that are much warmer. While the globe may increase 1°C, the continents will be around 1.25-1.5°C warmer. The figure also shows that the warming will be even higher in the Arctic regions, because the localised ice-albedo feedback will allow an increase in absorbed radiation.

 

The final verdict on 2014 is still to come, but it will likely not be a surprise.

Tweet of the week - Arctic Report Card

In the last post we saw when the Antarctic and Arctic cooled enough to allow the formation of ice sheets. Now the Arctic is warming at an alarming rate. NOAA has an Arctic Report Card were it presents the state of the Arctic based on Snow covered days, albedo, ocean temperatures and even polar bears!

#Arctic warming twice the global average. Will #Santa have to move? http://t.co/Z6RzF6JWWh pic.twitter.com/1AZePNl8s9
— NOAA Climate.gov (@NOAAClimate) December 24, 2014

End Permian Mass Extinction

Finally, the big one. Around 90% of all species went extinct: 70% of land vertebrates and 80-96% marine animals (Chen & Benton, 2012). After millions of years of living beings surviving the challenges of the changing Earth, what happened that almost wiped them out?

Fig. 1: A marine ecosystem before and after the mass extinction. Chen & Benton, 2012. © John Sibbick

The end Permian extinction event was 252 million years ago and it happened "quickly", in less than 100,000 years (Shen & Bowring, 2014). The exact causes are still debated, though there is one that stands out. This time the culprit seems to be volcanism (Payne & Clapham, 2012) - though not a lone volcano erupting, but massive eruptions, flooding extensive areas with over 5 million km³ of basalt. The eruption of the Siberian traps, located in central Russia, went on over a period of 1 to 2 million years (Shen & Bowring, 2014). The volcanic activity released huge amounts of CO₂ to the atmosphere; this could have even been increased due to interactions with organic deposits. Svensen et al. (as cited by Payne & Clapham, 2012) calculated that over 30,000 GT of carbon was released to the atmosphere! As you probably expect, there is evidence for a rise in global temperatures of around 8°C (Shen & Bowring, 2014). 

However, not only did the CO₂ influence the temperature; it likely caused ocean acidification and carbonate saturation. This would affect the marine animals, specially those with shells, leaving them without refugia (Payne & Clapham, 2012). 

Another mechanism involved in the extinction was marine hypoxia/anoxia, perhaps caused by the excessive chemical weathering of the Siberian traps, releasing phosphorous to the oceans (Payne & Clapham, 2012). The excess nutrients would have promoted eutrophication and hypoxia.

The emissions from the eruptions would have included not only CO_2, but sulfur, HCl and CH₃Cl, among others. Black et al. (2014) used a model to assess the effect of these emissions on the ozone layer and acid rain with different eruption scenarios. They found that the ozone layer could have been depleted up to 30% due to HCL and up to 67% due to CH₃Cl when these emissions reached the atmosphere. The effects would have been felt worldwide - increased UV B radiation with mutagenic effects. For the acid rain they considered a CO₂ concentration 10 times higher than present. This effect alone would have meant acid rain with a pH of around 4, and it would have been present worldwide. Combined with sulfate, for a 1 year eruption of 2400 km³, the pH may have dropped as low as 2, with the effects mainly in the Northern hemisphere (the location of the traps).

It took about 8-9 million years for life to make a full recovery (Chen & Benton, 2012), after almost being wiped out in 100,00 years. But this mass extinction paved the way for a new revolution of life, and the soon to begin age of the reptiles.

RIP
520 - 252 million years ago
Source: Wikipedia.com

Tweet of the week - The weather in 2050

This week, as part of the UN Climate Change Conference in Lima, the WMO has been releasing a daily video with a weather report of a day in 2050 for different countries. These reports are based on a climate change scenario where we keep increasing our greenhouse gas emissions - and they are quite alarming!

#Weather2050 reports. Today from Vietnam. Climate change is already happening #COP20 http://t.co/qeGt8Qrnby pic.twitter.com/j1eeWGzDYO
— WMO | OMM (@WMOnews) December 3, 2014

You can find all the videos (including an earlier batch of videos released in September during the UN Climate Summit) in the WMO website.

Here is the one for Spain, remembering the 2010 heatwave with some "nostalgia".