Wednesday, May 29, 2013

Kiribati's battle against sea-level rise: the perception and the reality

Last year, I published an article (Donner, 2012) reflecting on years of field work in Kiribati:

Tarawa, the most easily accessible atoll in Kiribati, is a popular destination for journalists and activists interested in observing and communicating the impacts of sea-level rise on a low-lying nation... common images of flooded homes and waves crashing across the causeways—collected during an anomalous event on islets susceptible to flooding due in part to local modifications to the environment—can provide the false impression that Tarawa is subject to constant flooding because of sea-level rise.

Kiribati's Abaiang Atoll (photo by author)
Tarawa and the rest of Kiribati are certainly under serious long-term threat from sea-level rise. The concern expressed in last year's paper is the effects of shoddy research and loose talk by journalists and climate activists, inside and outside of Kiribati, about specific events:

Such unverified attribution can inflame or invite skepticism of the scientific evidence for a human-caused increase in the global sea-level. 

I now bring you Exhibit A: "Kiribati: A Nation Going Under" by Bernard Lagan in the Kiwi publication the Global Mail, published a couple weeks ago when I was in the field.

Running out of options, and water, a nation’s leader enters an end game against climate change.  The President of Kiribati urges an orderly evacuation — “migration with dignity”.

Rare among international coverage of Kiribati, the article goes into accurate detail about the many local issues beyond climate change and is tough on President Anote Tong, who is usually lionized by the international press. Yet the article still butchers the evidence for impacts of sea-level rise, falling for the tempting bait I describe in the Donner (2012): flooding and erosion caused by climate variability and shoreline modification. It is a shame because otherwise, the article is one of few I've seen to capture the complex politics of responding to threats of climate change in this remote, developing nation.

Along comes Andrew Bolt, a skeptical writer from Australia. He does what I'll guess was a few minutes of research with Google, and then raises loud objections in the two bluntly-titled articles: "Are the satellites lying about poor drowning Kiribati?" and "Look at this other drowning island, the Global Mail writer insisted. So I did.

Most of Bolt's claims are ridiculous or sloppy. First, he tries to eyeball changes in Tarawa's land area using Landsat satellite imagery over a 12 year period. This would be like standing at the finish line of a 100 m race and trying to spot individual hairs on the heads of the sprinters in the starting blocks. Second, like many other journalists, he mistook reports that some islets expanded in area over past decades (Webb and Kench, 2010) as evidence that the islets are not being affected at all by sea-level rise. Think of it this way: islands can expand in surface area over time due to land reclamation and natural beach movement and still become "lower" and suffer saltier groundwater because the ocean is higher. Third, Bolt uses second-hand sources, citing selected text from a blog post on my work, rather than reading my work or dropping me a line.

Nonetheless, buried in the muck are some correct assertions, and the overall argument will come across as reasonable to many readers. The end result of an otherwise good Global Mail article is confusion about whether sea-level rise is affecting Kiribati.

How can this be avoided? More care in reporting about sea-level rise would help. The Global Mail article features three classic mistakes made by journalists and climate activists:

1. People are leaving a low-lying island so it MUST be a result of sea-level rise

Sea-level rise could very well lead to mass migration between atolls and from Kiribati to other countries. Is it happening now? The Global Mail:

But some outer islands are also being invaded by the sea. Their fragile fresh water reserves stored naturally beneath the ground are dying away and more and more displaced outer islanders are flocking to Tarawa.

Lagan's repeating an assertion commonly made by climate activists in and out of Kiribati. In reality, migration to Tarawa is driven largely by Kiribati's transition to the cash economy and the desire for jobs, as Bolt correctly asserts in his article. This is no secret; the same dynamic is at play in many developing countries. And had Lagan done some digging, he would have found that freshwater pressure on outer islands has always existed; people voluntarily evacuated in the 30s and 40s from the Southern Gilberts.

2. Land is eroding, so it MUST be because of sea-level rise

Sea-level rise will certainly erode Kiribati shorelines. But not every case of erosion you are shown in a short visit to Kiribati is actually due to
El Nino driven flood of 2005 (photo by auth
sea-level rise. The Global Mail:

Elsewhere on Abaiang Atoll, one village, Tebunginako, which villagers have battled to save for the past 30 years from the encroaching sea, has had to be moved inland — a development that is often referred to as hard evidence that Kiribati is being ravaged by climate change.

Ask yourself a question. If atolls feature long narrow strips of land, why would one village erode away by tens of metres more than the neighbouring villages? A quick internet search is all that's needed to uncover the very clear 2005 report by the South Pacific Applied Geoscience Commission (SOPAC) about Tebunginako. The village was built long ago on the sand spit created by a former passage between the lagoon and the outer island. It's eroding because of "shoreline processes consistent with an ocean / lagoon passage". Village consultations were done, and the evidence was accepted, as it agreed with the local oral history. People agreed that given the land was naturally eroding, it made more sense to move their homes than to build sea walls.

3. A weather extreme affected the shoreline, so the extreme MUST be caused by climate change

Once again, the Global Mail:

Yet, as far back as 1992, a technical report, funded by the Canadian government, said increasingly severe El Niño events were producing the large waves that were eroding the Abaiang coast... Only very recently — in the past year or two — have some climate scientists begun to suggest a strong link between severe El Niño events and global warming. However, this link is still contested among scientists.

In this case, it is worth talking to a climate scientist about El Nino events. Weather and high seas during El Nino events certainly lead to wave inundation in Kiribati, an issue I discuss in depth in Donner (2012). The El Nino driven variability in sea-level, ocean temperatures and wind direction is one thing that makes Kiribati so unique. Unfortunately, the desire to blame the El Nino inundation events on climate change has driven most of the flawed international coverage of climate change in Kiribati. Though flooding during already high water El Nino events is certainly statistically more likely to happen as global average sea-level rises, the events themselves are no more evidence of rising sea-level than an individual heat wave is evidence of rising global temperatures.

What to do

Climate change is frustrating. Though unprecedented in recent geological history, human-caused climate change still operates at too slow a pace to capture much of the public's attention. So people try to attribute current events to the long-term trend, and often make elementary mistakes: I'll end with my recommendation from my article:

Instead of incorrectly attributing individual flood events or shoreline changes to global sea-level rise, scientists and climate communicators can use such occurrences to educate the public about the various natural and human processes that affect sea-level, the shoreline, and the shape of islands. This would better prepare the public and policy makers for the changes that societies are likely to experience as global sea-level rises in the coming decades.

So journalists and climate activists: Before and after you go to Kiribati, or Tuvalu, or the Maldives, please call a scientist that works there. It will save us all a lot of trouble.


Bruce of Newcastle said...

Dr Morner's very recent paper suggests sea level rise will be 5 inches by 2100.

I suspect the net rise for Kiribas is more strongly due to the cooling contraction of the geology, but sand deposition would tend to offset this anyway. Seems unlikely there would be any problem for them, really.

Also sea level rise is decelerating markedly as we get into the cool phase of the PDO and the solar minimum. I don't think they need to worry.

Simon Donner said...

While there is strong inter-annual variability in sea level in Kiribati, there is also a clear trend in the gauge data, which goes back many decades, a trend that is quite clearly due to climate change, not geological contraction. If geology were the driving factor, the trend would be in the other direction.

Col said...

Willis eschenbach covers the dynamics of coral reefs nicely here

Simon Donner said...
This comment has been removed by the author.
Simon Donner said...

Er, no. Eschenbach completely whiffs on the three core arguments in that post, using incorrect analogies and incorrect mixing of time scales (of atoll construction and modern sea level rise). I expect the errors discussing drivers of sea level rise from someone who is already openly questioning climate change, but the argument that you can't flood a freshwater lens with salt water is lunacy. It happens all the time.

Also, like a lot of other people, he completely misinterprets Webb and Kench (2010), which despite press coverage at the time, does NOT argue the islands are moving "upwards" over time (I'll give Eschenbach the benefit of doubt and assume he does not actually think islands "float" upwards). Webb himself debunked that argument on the SOPAC website in the aftermath of confused press coverage.

There is still some value to Eschenbach's post; some of the "practical suggestions" would help places like Kiribati manage erosion problems and adapt to sea level rise. They will prove insufficient if we do nothing to address the drivers of sea level rise, but they are still valuable.

There is a lesson here: we can reach some - some, not all, similar policy recommendations despite completely disagreement on science.