Boreal forest on the edge of a climate-change tipping point

15 11 2016

As some know, I dabble a bit in the carbon affairs of the boreal zone, and so when writer Christine Ottery interviewed me about the topic, I felt compelled to reproduce her article here (originally published on EnergyDesk).

A view of the Waswanipi-Broadback Forest in the Abitibi region of Northern Quebec, one of the last remaining intact Boreal Forests in the province (source: EnergyDesk).

A view of the Waswanipi-Broadback forest in the Abitibi region of northern Quebec, one of the last remaining intact boreal forests in the Canadian province (source: EnergyDesk).

The boreal forest encircles the Earth around and just below the Arctic Circle like a big carbon-storing hug. It can mostly be found covering large swathes of Russia, Canada and Alaska, and some Scandinavian countries.

In fact, the boreal – sometimes called by its Russian name ‘taiga’ or ‘Great Northern Forest’ – is perhaps the biggest terrestrial carbon store in the world.

So it’s important to protect in a world where we’re aiming for 1.5 or – at worst – under two degrees celsius of global warming.

“Our capacity to limit average global warming to less than 2 degrees is already highly improbable, so every possible mechanism to reduce emissions must be employed as early as possible. Maintaining and recovering our forests is part of that solution,” Professor Corey Bradshaw, a leading researcher into boreal forests based at the University of Adelaide, told Energydesk.

It’s not that tropical rainforests aren’t important, but recent research led by Bradshaw published in Global and Planetary Change shows that that there is more carbon held in the boreal forests than previously realised.

But there’s a problem. Read the rest of this entry »

Missing the forest despite its trees

21 04 2015

An exchange on over the intactness of boreal forests has just erupted. Bill Laurance asked me to weigh in as an independent appraiser of the debate, so I copy my thoughts below. You can read the original exchange between Jeff Wells and Nick Haddad (& colleagues) here.

Despite its immense size, there is little doubt that the ugly second cousin of forest conservation is the boreal region covering much of Alaska, Canada, Fennoscandia and Russia. Indeed, extending some 1.4 billion hectares, of which well over 60% is found in Russia alone (1, 2), the entirety of the boreal forest is more than double the area of the Amazon forest. Yet despite this massive expanse, the impressive biota it shelters (2), and its important contribution to the global carbon (1), nitrogen (3) and oxygen (4) cycles, the boreal is an oft-overlooked region in terms of global conservation priorities and possibilities (5).

The exchange between Haddad & Sexton and Wells regarding the former researchers’ recent paper (6) highlights this problem, of which even many expert ecologists are often only vaguely aware. Wells takes particular issue with Haddad and colleagues’ assertion that the boreal forest is highly fragmented, claiming to the contrary that the (North America) boreal forest is “… truly intact … ”. While Haddad et al. respond that they did not differentiate between ‘natural’ and human-caused fragmentation, my view is that the exchange misses some important concerns about the state of the boreal forest.

Wells correctly points out that the boreal zone in North America is “massive”, but can his other claim – that it is “truly intact” – stand up to scrutiny? Citing one of my own papers from 2009 (2) to demonstrate (correctly) that the boreal forest of North America holds a stunning array of species, Wells neglects to highlight that in that same paper we also identified the extensive, artificial fragmentation that has occurred there and in other parts of the boreal zone over the last few decades. For example, we showed clearly that only 44% of the entire biome is considered to be ‘intact’, defining the term precisely as “areas ≥ 500 km2, internally undivided by infrastructure (e.g., roads) and with linear dimensions ≥ 10 km”. Satellite imagery has also confirmed that between 2000 and 2005, the boreal biome experienced the largest area of gross forest cover loss compared to any other (7). Despite recent evidence that so-called edge effects (characteristics of a disturbed matrix that penetrate some distance into habitat fragments) are probably of a smaller spatial magnitude in boreal compared to other biomes (8), it is disingenuous to claim that North America’s boreal forests are “truly intact”. Read the rest of this entry »

Earth’s second lung has emphysema

19 02 2015


Many consider forests as the ‘lungs’ of the planet – the idea that trees and other plants take up carbon and produce oxygen (the carbon and oxygen cycles). If we are to be fair though, the oceans store about 93% of the Earth’s carbon pool (excluding the lithosphere and fossil fuels) and oceanic phytoplankton produces between 50 and 80% of the oxygen in the atmosphere. For comparison, the terrestrial biosphere – including forests – stores only about 5% of the Earth’s carbon, and produces most of the remainder of atmospheric oxygen.

So there’s no denying that the biggest player in these cycles is the ocean, but that’s not the topic of today’s post. Instead, I’m going to focus on the terrestrial biosphere, and in particular, the carbon storage and flux of forests.

Now it’s pretty well established that tropical forests are major players in the terrestrial carbon cycle, with the most accepted estimates of about 55% the terrestrial carbon stock stored therein. The extensive boreal forest, covering most of the northern half of North America, most of Scandinavia and a huge chunk of Russia, comes in globally at about 33%, and temperate forests store most of the remainder.

That is, until now. Read the rest of this entry »

Eye on the taiga

24 03 2014

boreal damageDun! Dun, dun, dun! Dun, dun, dun! Dun, dun, daaaaah!

I’ve waited nearly two years to do that, with possibly our best title yet for a peer-reviewed paper: Eye on the taiga: removing global policy impediments to safeguard the boreal forest (recently published online in Conservation Letters).

Of course, the paper has nothing to do with cheesy Eighties music, underdog boxers or even tigers, but it does highlight an important oversight in world carbon politics. The boreal forest (also known as taiga from the Russian) spans much of the land mass of the Northern Hemisphere and represents approximately one quarter of the entire planet’s forests. As a result, this massive forest contains more than 35% of all terrestrially bound carbon (below and above ground). One doesn’t require much more information to come to the conclusion that this massive second lung of the planet (considering the Amazon the first lung) is a vital component of the world’s carbon cycle, and temperate biodiversity.

The boreal forest has been largely expanding since the retreat of the glaciers following the Last Glacial Maximum about 20,000 years ago, which means that its slow progression northward has produced a net carbon sink (i.e., it takes up more atmospheric carbon that it releases from decomposition). However, recent evidence suggests that due to a combination of increased deforestation, fire from both human encroachment and climate change, mass outbreaks of tree-killing insects and permafrost melting, the boreal forest is tipping towards becoming a net carbon source (i.e., emitting more carbon into the atmosphere than it takes up from photosynthesis). This is not a good thing for the world’s carbon cycle, because it means yet another positive feedback that will exacerbate the rapid warming of the planet. Read the rest of this entry »

Get boreal

7 06 2012

I’ve been a little quiet this last week because I’ve had to travel to the other side of the planet for what turned out to be a very interesting and scientifically lucrative workshop. After travelling 31 hours from Adelaide to Umeå in northern Sweden, I wondered to myself if it was going to be worth it for a 2.5-day workshop on a little island (Norrbyskär) in the Baltic Sea (which, as it turned out, didn’t have internet access).

The answer is a categorical ‘yes’!

Many of you know that I’ve dabbled in boreal forest conservation in the past, but I could never claim any real expertise in the area. Hence it came as something of a shock when Jon Moen of Umeå University asked me to attend a specialist workshop focused loosely on making the plight and importance of the boreal forest more widely acknowledged. I dragged my feet initially, but Jon convinced me that I could add something to the mix.

It was a small workshop, but well-represented by all boreal countries save Norway (i.e., we had Russians, Swedes, Finns, Canadians and Americans – this Australian was indeed the odd one out). We also had a wide array of expertise, from carbon accountants, political scientists, political economists, native cultures experts, ecologists to foresters. Our mandate – justify why we should pay more attention to this globally important region.

Just how important is the boreal forest? We managed to unearth some little-appreciated facts: Read the rest of this entry »

Sink to source – the loss of biodiversity’s greatest ecosystem service

29 02 2012

I’ve mentioned this idea before, but it’s nice when some real data support a prediction (no matter how gloomy that prediction might have been). It’s what drives scientists toward discovery (or at least, it’s what I find particularly appealing about my job).

Several years ago, my colleagues (Navjot Sodhi† and Ian Warkentin) and I wrote a major review in TREE about the fate of the world’s ‘second’ lung of the planet, the great boreal forests of Russia, Canada & Scandinavia. We discussed how fragmentation was increasing at an alarming rate, and that although most species there are still relatively intact, we stand to lose a lot of its biodiversity if we don’t halt the fragmenting processes soon. We wrote more on the subject in a paper to appear imminently in Biological Conservation.

Another component though that we raised in the TREE paper was the boreal forests were very much in danger of turning into a net carbon producer. You see, the ‘lung’ analogy is very pertinent because on average, the growth of the massive expanse of the vegetation in the forest generally takes up much more atmospheric carbon that it exudes through decay and burning (for as we all know, plants take up carbon dioxide to produce sugars during photosynthesis, and produce oxygen as a ‘waste’ product). However, as we fragment, cut down and burn the forest, it can end up producing more than it takes up (i.e., turning from a ‘sink’ to a ‘source’). We highlighted several studies indicating how insect outbreaks and human-exacerbated fire intensities and frequencies could conceivably do this.

Now Zhihai Ma and colleagues have just compiled a paper in PNAS indicating that the danger is well on the way to becoming reality in Canada. The paper entitled Regional drought-induced reduction in the biomass carbon sink of Canada’s boreal forests reports the results from 96 long-term permanent sampling plots spread right across southern Canada – from British Columbia in the far west, to Newfoundland in the far east. Read the rest of this entry »

Slicing the second ‘lung of the planet’

12 12 2011


Apologies for the slow-down in postings this past week – as many of you know, I was attending the International Congress for Conservation Biology in Auckland. I’ll blog about the conference later (and the stoush that didn’t really occur), but suffice it to say it was very much worthwhile.

This post doesn’t have a lot to do per se with the conference, but it was stimulated by a talk I attended by Conservation Scholar Stuart Pimm. Now, Stuart is known mainly as a tropical conservation biologist, but as it turns out, he also is a champion of temperate forests – he even sits on the science panel of the International Boreal Conservation Campaign.

I too have dabbled in boreal issues over my career, and most recently with a review published in Trends in Ecology and Evolution on the knife-edge plight of boreal biodiversity and carbon stores. That paper was in fact the result of a brain-storming session Navjot Sodhi and I had one day during my visit to Singapore sometime in 2007. We thought, “It doesn’t really seem that people are focussing their conservation attention on the boreal forest; how bad is it really?”.

Well, it turns out that the boreal forest is still a vast expanse and that there aren’t too many species in imminent danger of extinction; however, that’s where the good news ends. The forest itself is becoming more and more fragmented from industrial development (namely, forestry, mining, petroleum surveying and road-building) and the fire regime has changed irrevocably from a combination of climate change and intensified human presence. You can read all these salient features here.

So, back to my original thread – Stuart gave a great talk on the patterns of deforestation worldwide, with particular emphasis on how satellite imagery hides much of the fine-scale damage that we humans do to the world’s great forests. It was when he said (paraphrased) that “50,000 km2 of boreal forest is lost each year, but even that statistic hides a major checkerboard effect” that my interest was peaked. Read the rest of this entry »