El Niño: The Good, The Bad, and The Ugly

This blog started off considering how ocean temperatures have been rising, specifically since the start of the Industrial Revolution, when El Niño started hitting the news headlines. El Niño led the direction of this blog, as it is something we are all experiencing and can all relate to, no matter your previously knowledge. Together we’ve learnt about just what El Niño is, and considered the forecasts made for the winter of 2015 and into the spring of 2016. We’ve looked at El Niño in relation to global warming, considering both the cases that El Niño is causing global warming (don’t worry, we quickly put that theory to rest!), and the effect that global warming is having on El Niño events. We looked at the different types of models used in relation to ENSO, specifically statistical and dynamical forms, and discussed the advantages and disadvantages of each of them. We’ve looked at how you can contribute to the bigger picture, and why it is that sometimes models just don’t quite get it right. If you’ve missed any of this, catch up with my previous posts!

So, what is next for the current ‘monster’ El Niño?

The latest satellite images have been released from NASA showing that the current El Niño event is showing no signs of weakening just yet...

Source: Jet Propulsion Lab, NASA.

Since I last posted the NASA satellite images from 16^th October 2015, the area of unusually high sea surface temperatures across the Pacific Ocean has increased. As can be seen in the latest images from 27^th December 2015 above, there is a large expanse of red-white spreading from the Chilean coast up to the north of the Mexico’s west coast, and reaching far into the centre of the Pacific. As you may remember from an earlier post, these images show sea surface height anomalies, which are highly correlated to temperatures and the heat stored within the ocean below. The areas of white highlight sea surface that is between 15 and 25 centimetres above normal.  Conversely, the region of blue-purple showing sea levels up to 25 centimetres below average has decreased since my October post.  

The movie below shows the evolution of sea surface height anomalies since the beginning of 2015 alongside the corresponding ones from 1997, when the previous immense El Niño was felt around the world. 

The 1997 El Niño was recorded by the NASA/Centre National d'Etudes Spatiales (CNES) Topex/Poseidon mission, whilst the current event is captured by the Jason-2 satellite. It can be seen that there is a remarkable likeness between the two, which both display the typical development of an intense El Niño. Given an El Niño on the same scale as that of 1997/98, what does this mean for the planet and society?

El Niño: The Good

I stumbled across this really interesting project that one of our own UCL Geographers (PhD student David Seddon), supervised by Professor Richard Taylor, is currently researching. A small wellfield in a semi-arid basin called Makutapora in Tanzania, supplies the countries capital city, Dodoma, with safe water. Replenishment of this vital source of freshwater for hundreds of thousands of people  has shown to occur in conjunction with El Niño events. The immense El Niño that we are currently experiencing will no doubt have an effect on these resources, and the GroFutures team have set up instruments to monitor it. This blog has largely focussed on the negative impacts of El Niño, but this project highlights that episodes are also of crucial importance in some parts of the world that desperately need groundwater levels replenished. 

El Niño: The Bad

A recent study by Chretien et al., (2015) shows that during El Niño events the effects not only impact on the environment, as we’ve seen by flooding and drought, but this incidentally impacts on global health by possibly increasing the spread of infectious disease. Malaria, chikungunya, and dengue are all very nasty illnesses that you do not want to catch! They are spread by mosquitoes, which thrive under the wet conditions El Niño brings to South and Central America, and parts of the US. Conversely, areas which feel the warm, dry impacts of El Niño may see increases in the transmission of cholera, and other infectious diseases. Powerful El Niños also have a long-term impact on coral reefs. A 17 year study of coral reefs in Bahia, Brazil, found that for two years after the 1997/98 El Niño there was severe coral bleaching and a significant reduction in size. In other areas of the world including the Indian Ocean, this was significantly worse. It took 13 years for the coral in Bahia to fully recovery. 

El Niño: The Ugly

The shift in temperature and precipitation levels that coincide with El Niño events impacts on the global yields of major crops. This undoubtedly has knock-on effects to food prices. Lizumi et al., (2014) considers the global effect of ENSO on crop yield, and finds that El Niño results in maize, rice and wheat harvest changing between −4.3% and +0.8%. However, this is not the case for soybean yield, which actually increases by 2.1% to 5.4% under El Niño conditions. Lizumi et al., (2014) expects that the global demand for these crops will increase by 100–110% by 2050 from that in 2005. Close monitoring of the ENSO cycle is crucial in minimizing the negative impacts and maximizing the positive impacts that El Niño and La El Niña have on crops. Cashin et al., (2015) consider not only the countries that are directly affected by El Niño, but also the indirect macroeconomic effects filtered through third-markets. 21 country/region-specific models are analysed, from 1972 to 2013, to see how growth, inflation, energy and non-fuel commodity prices differ under El Niño conditions. The study finds the majority of countries analysed experience energy and non-fuel commodity price increases in the short term, however the EU and US actually see a growth effect! Unfortunately this isn’t the case for Australia, Chile, Indonesia, India, Japan, New Zealand and South Africa who see a downfall in economic activity.

Whether ‘The Good’, ‘The Bad’, or ‘The Ugly’, modelling can be used as a tool for preparing for these situations, either by harnessing the conditions that El Niño brings, or, protecting against it.

What is next for Modelling?

A report published by Rädel et al., only 5 days ago, used the Earth system model, MPI-ESM-LR, to analyse the role of clouds in El Niño. The study found that atmospheric circulation is highly affected by cloud processes, and this contributes to more than half the intensity of the El Niño. Climate models that didn’t take the interaction of clouds with atmosphere circulation into account would therefore predict a weaker El Niño than those which did consider the interaction. Back in 2012, Maslin and Austin discussed whether climate models were already at their limit. They argued that the complex climate models in use are likely to produce predictions with more uncertainty due to the increased complex factors such as interactive carbon cycles, and the role of aerosols in atmospheric chemistry now included within the models. In relation they express the importance of the public and policymakers being aware that “climate models may have reached their limit”. Whilst I agree that the public and policymakers should have an understanding that a model is not an exact reproduction of the reality, hence has its limitations and will not always predict exactly as reality turns out to be, I fear that a statement worded in such a way will in fact decrease public support of scientific modelling, rather than the intended increase of support. We should not stop adding further details to current models for fear of them performing worse. As the study by Rädel et al., (2016) found, sometimes complex processes do need to be included within models. As our understanding and technology advances so will the certainty of these models. Models of all complexity have a role to play; as Knutti (2010) succinctly put it, “we learn from the diversity of models, and we will learn from different ways to evaluate and combine them”.