El Niño 2015 could rival strongest events on record: NOAA

Thursday, August 13, 2015, 7:49 PM - Experts from NOAA say El Niño 2015 could rival the top events on record, a "detectable effect" of climate change is seen in Texas' May floods, and August 13 is now Earth Overshoot Day 2015. It's What's Up In Climate Change!

El Niño 2015 could be one of the strongest on record

The latest update from NOAA's Climate Prediction Center on the status of El Niño was released on Thursday, and forecasters are doubling down on the persistence of this event, and predicting big things for when it reaches its peak in the months to come.

"We’re predicting that this El Niño could be among the strongest El Niños on record, dating back to 1950," CPC Deputy Director Mike Halpert said during a press teleconference on Thursday.

The strongest El Niño pattern recorded so far, since 1950, took place in 1997/98, when sea surface temperatures in the central region of the equatorial Pacific Ocean (as recorded on the Oceanic Niño Index - ONI) reached 2.3°C above normal. The second strongest was in 1982/83, when ONI was 2.1°C above normal in that region of the ocean.

So far, the latest three-month average sea surface temperature from this "Niño 3.4" region, for May-June-July, shows that they are 1.0°C above normal, and the values have been climbing since March. The latest sea surface temperature anomaly map is compared below with the closest satellite reading from 1997, and there's a striking similarity.

Credit: NASA JPL

Based on computer model results, the CPC forecast team's latest consensus on how El Niño will develop from here shows that it may reach between 2.1 and 2.2 on the index by the time they document the Nov-Dec-Jan average.

While this forecast is not set in stone, and some model runs (shown to the right) favour the pattern weakening earlier in the year, there has been a shift in more recent forecasts to a stronger and longer-lived event. Also, even though some model runs go so far as to predict what could be called an "ultra" El Niño - one that would far surpass the "super" El Niño of 1997/98, reaching over 3.0 on the ONI - those would seem to be the "outliers" on the graph, and this is likely not going to happen.

Even so, while El Niño 2015 may not beat out the "super" El Niño, it will still likely have significant impacts on weather across North America, and - if it isn't guaranteed already - it would certainly loft 2015 to the top of the list of hottest years on record.

"Detectable effect" of climate change spotted

When extreme weather events occur, one of the common questions that comes up these days is "Was this caused by climate change?" However, since climate change is the long-term pattern of changing weather, it's very difficult to see it in short-term weather events.

When researchers from Utah State University and two Taiwanese institutions examined the extreme rainfall in Texas during May 2015, when over 140 trillion litres of water fell on the state over that month, they found "a detectable effect of anthropogenic global warming" in the conditions and processes that caused this month-long deluge and the resulting flooding.

According to ThinkProgress, lead researcher Simon Wang, of the Utah Climate Center, said:

Basically, we linked the weather conditions that caused the consecutive and high amounts of rainfall to two main climate sources: (1) El Niño and its enhanced teleconnection owing to the warming Pacific temperature and (2) middle latitude circulation that is becoming increasingly "wavy," causing the trough (or any ridge for that regard) to stick around for a long time.
Identifying (1) and (2) is crucial because this event (very wet May in TX-OK) was forecast 3 months earlier by operational climate forecast models. What wasn’t forecast is the extreme magnitude. It is an important progress by climate forecasting community! Knowing that El Niño impact will increase can potentially help (climate) forecasters better anticipate extreme events.

Earth Overshoot Day 2015

As we humans use up the natural resources of Earth, emit waste from our industries and households and emit carbon pollution into the air, the planet's ecosystem only has a limited ability to replenish those resources and absorb those waste products.

When human activities exceed the planet's current capacity to balance the results of those activities, we have Earth Overshoot Day - when we have, effectively, used up nature's "budget" for the year.

WATCH BELOW: Alexandre Magnin explains in this video produced for Earth Overshoot Day and the Global Footprint Network.

Global Carbon Dioxide

Credit: Scripps Institution of Oceanography

Sources: NOAA | Climate Central | Think Progress | Earth Overshoot Day