A week ago, the UN Intergovernmental Panel on Climate Change (IPCC) delivered to massive media coverage an unsettling message – climate change is real, humans are the main cause of it, and unless we stop the warming of the planet, in 50 years life as we know will be no more. The problem now, is that despite in numerous attempts, world consensus on how to do it has proved impossible.

Research in Nature Climate Change by
a Portuguese team known worldwide for their studies on cooperation claims to have not only identified the root of the problem but also its solution.

Vítor Vasconcelos, Francisco Santos and Jorge M. Pacheco from the
ATP-group at Lisbon used game theory – a branch of mathematics that studies human social interactions – to look into the problem, and found that the key was “scale”. Their work showed that cooperation for climate control will only be possible if approached at regional or domestic level, with local institutions sanctioning those that do not collaborate (free-riders).

But not just that, as Pacheco, the team leader explains “ Our most
striking result was to find that punishment by global institutions – which at
the present situation would be the most logical choice – is almost like
applying no punishment. “ The data supports what many believe: that polycentric
governance (with many centers of authority) is more effective solving global
problems than a central international authority.

The findings calls for an urgent revision of the current approaches to
climate agreements, and could have not come at a more relevant time with the
IPCC now reunited to decide on measures to reach climate change mitigation.

So why are we experiencing global warming?

Despite the media space given to “climate change deniers”, there is an
overwhelming scientific consensus that the major cause of global warming is an
increase of greenhouse gases (such as carbon dioxide and methane) from human action, such as fossil fuel burning, expansion of landfills sites, deforestation, etc. This because earth’s temperatures result from, not only the incoming sun energy, but also the “greenhouse effect” (where heat released by earth is absorbed and sent back to the surface by the greenhouse gases in the atmosphere). So as the quantity of greenhouse gases increase by human action, so the heat absorbed and radiated back to earth, and also global temperatures.

Once this became clear, environmentalists everywhere started asking for
a control of greenhouse emissions and in 1998, the Kyoto Protocol, which
establishes targets to reduce greenhouse emissions, brought some hope that this
could be possible. But 18 meetings and 192 countries’ signatures later, still
only a handful of nations are following its directives. A clear obstacle is the
fact that the risk of climate catastrophe is (wrongly) perceived as low, since
it is far in the future. 

 So how to “force” the world
towards climate control?

It is now believed that the solution has to be an effective sanctioning/punishing
system, capable of deterring those that contemplate escaping their climate
control obligations.

In the study now published the researchers use game theory, which not
only models human strategic interactions, but can also predict the best conditions
for a behaviour to emerge (like cooperation towards climate control), to test
different types of sanctioning.

In 2011, Pacheco’s group had already demonstrated using game theory that
current approaches – global summits where countries meet in one single group to
try achieving an agreement on climate change – were actually detrimental for
cooperation.

In the new work they look into using instead local institutions to
promote a climate agreement, and test how different types of sanctioning could
influence the outcome

 So how does game theory work?

The idea is to design a series of mathematical equations that represent
the strategic game we want to test. In this case we have a public good game, where the “public
good” (a global good from which everyone benefits, whether they contribute
for it or not) is the welfare of the planet, and the aim is to find the
conditions necessary to make the players cooperate protecting the planet. A
catch is that cooperation in here is not to gain something, but to avoid the
risk of collective loss (catastrophic climate change) what makes an agreement
harder to achieve.

There also two extra obstacles: first the fact that players see the risk
of climate disaster as low, and second that the game only has a positive
outcome if most players curb enough emissions otherwise everyone will lose. And
the problem is that nobody knows what others will do, so it is not clear how
much is enough. This, together with cooperation implying sacrifices, makes the
chances of free-riders appear very high (like the Kyoto agreement’s results so
well demonstrate).

Like in any game, there are players and they can be either be co-operators (C) or defectors/non-co-operators (D), but
since the Portuguese wanted to test the effect of sanctioning, they added punishers (or P), who are co-operators
that contribute also for a sanctioning institution. Like in real life, the
players can adapt their behaviour (from being a C to a D for example), as they
see what others are doing.

If you do not want to know about the
maths behind the findings look away now
(and go to “Results”)

Once
a model that included all these conditions was put in place, Vasconcelos and colleagues started by calculating
the population’s Stationary Composition
- which gives the population most likely set of behaviours
(C, P and D), by finding the length of time each different combination of C/D/P
lasts (for example how long for 40% Cooperators+40%Punishers+20% Defectors).

From
this, they can find Institutions
Prevalence - the time a sanctioning institution lasts, and, most importantly, Group Achievement, which gives the
number of groups that cooperate, or, basically, how successful (or not) the
cooperation is

Then, to identify the best conditions
to achieve cooperation, the researchers investigated how these 3 parameters (and
especially group achievement) vary with different conditions, in particular ,
different levels of risk perception in 3 situations: when there is no
sanctioning of free-riders, when the sanctioning is being done by a global
institution and when is done, instead, by several local institutions.

Results

The Portuguese researchers team's results showed that cooperation grows with risk perception. Since
in climate change the risk is perceived as low, no surprise that a global
agreement has not been achieved.

 The good news is that this dynamic changes radically once sanctioning by
local institutions is introduced. In this case, cooperation is possible even
when the risk is seen as low. Surprisingly, punishment by a global institution
gives a pattern of cooperation similar to that found if there is no sanctioning
(which is directly dependent of risk size).

This last result is particularly important because it is not an
intuitive one (a global sanctioning institution is as effective as do nothing?)
and chances are that the IPCC, in its next report in April, will recommend
global sanctions mediated by a central international institution, which,
according to these results, will not work.

So why are local institutions so much more efficient cooperating even at
low risk perception? Vasconcelo’s study were able to identify a variety of reasons – for a start local
sanctioning institutions tend to last longer (promoting cooperation) than
global ones, and are easier to emerge acting as catalysers of collective action
while stopping free-riders.

The frequency that the individuals change behaviour (from cooperating to
become free-riders for example), and which the researchers show to increase the chance of
cooperation, is also higher in local institutions probably because these have
shorter-term goals allowing players to reassess their choices frequently.

Finally their work also shows that there has to be a minimum number/percentage
of punishers (co-operators that contribute to the sanctioning institution) to
trigger cooperation in a population, and with many local groups (instead of a
global one) there is a bigger chance that at least some will manage it (after
all in smaller populations a smaller number of punishers will be needed).

Vasconcelos and Pacheco’s new work crucially supports what the Economics
Nobel prize Elinor "Lin" Ostrom first proposed- that the resolution
of climate change lies in polycentric
governance; a governance coordinated at many different levels being more
effective than an international “top-down” approach (like the one we now have). 

It is easy to understand why - if climate change has different effects at multiple levels and
regions, governance by the groups directly affected has to have the higher
chance of success.

And there are already a few successful examples - one of the best-known
is the launch, in the 70s, by several US local governments of measures to
reduce air pollution (including greenhouse gases). A 2001 study of 51 of their
metropolitan areas showed that, in under 20 years, air pollution was diminished
by a third.  Other successful example is a program, in Berkley California,
that subsidizes the installation of solar panels in homes and businesses and
that has been hugely successful.

 As Pacheco so perfectly summarizes: “Climate control?
 Think globally, act locally” 

 ——————

Vítor V.
Vasconcelos Francisco C. Santos and Jorge M. Pacheco, 
A
bottom-up institutional approach to cooperative governance of risky commons
Nature Climate Change 3, 797–801 (September 2013) doi:10.1038/nclimate1927