Hacking the Climate: Can Geoengineering Solve Climate Change?

As humans marvel at their prowess in producing electro-mechanical creations, along with advances in materials engineering and synthetic chemistry, it may seem logical to address the problem of Earth’s changing climate purely as a technological problem to be solved at the global level. This avenue of thinking is quietly growing due to the risks of politicians dawdling and carbon emissions continuing unabated.

This way of thinking is called geoengineering, which is to deliberately intervene at a large scale in the planet’s natural systems to counteract climate change. There are annual conferences, research programmes at Oxford University, funding by the UK’s Engineering and Physical Sciences Research Council (EPSRC) and by billionaires, such as Bill Gates. Current research is to determine the feasibility of large scale intervention.

Geoengineering is the deliberate large-scale intervention in the Earth’s natural systems to counteract climate change.

Geoengineering is the deliberate large-scale intervention in the Earth’s natural systems to counteract climate change.

In 2009 the Royal Society published a report titled Geoengineering the Climate, and out of this grew research projects such as solar radiation management i.e. limiting how much sunlight the whole planet receives. One such project is called SPICE (Stratospheric Particle Injection for Climate Engineering) which is a collaboration between the Universities of Bristol, Cambridge, Edinburgh and Oxford along with the MET Office and Marshall Aerospace. The idea is to release reflective aerosol particles into the atmosphere decreasing inbound radiation.  Other types of projects relate to carbon dioxide removal, such as seeding the oceans with iron to create phytoplankton blooms.

Injecting particles into the stratosphere in order to affect global temperatures.

Injecting particles into the stratosphere in order to affect global temperatures.

Last year the US National Academy of Sciences released a report saying fiddling with the global climate now would be “irrational and irresponsible”, however, this was due to our lack of scientific knowledge, and thus urged policy makers to commit to geoengineering research now so that should it become needed, when all other plans fail, it will be a more informed decision. These research groups have experienced scientists on board, complete with ethics committees. This all sounds like a worthy research cause…or does it?

Firstly, let’s look at some practical and ethical issues surrounding the research, and secondly, the underlying narrative behind this way of thinking.

  1. Distributional Consequences

Countries may seek to control inbound radiation affecting their own landmass, however models have shown this to be highly disruptive to the climate in other parts of the world. This likely means developing countries due to their lack of resources, and how does one prove country A caused the severe storm in country B? This thinking also applies with ocean fertilisation.

  1. Conducting Experiments

Due to the size of the planet, physical tests done in the laboratory or even in a city will be largely meaningless when it comes to predicting global effects. This means a reliance on computer models until initiating the experiment in full – which is extremely risky.

  1. Solving the Root Problem?

Even if effective aerosols are launched or iron particles seeded, the root cause of carbon emissions will still be continuing with all the same political problems, plus now a distorted climate. As Naomi Klein drily notes, it means solving the pollution problem…with more pollution.

Removal of carbon dioxide from the atmosphere is the other proposed method of climate intervention, which the IPCC says is needed for most pathways towards a stable climate. One risky method already mentioned is ocean fertilisation, but others are more benign, for example carbon capture and storage, and expanding the use of bioenergy. Reforestation, while not a technology, is surely the most sensible of this type of intervention as it is beneficial to other life forms, while naturally absorbing carbon.

Reforestation makes the most sense.

Reforestation makes the most sense.

The thinking behind a large scale, technological, magic fix is not new. Its roots lie in religions’ portrayal of man’s dominion over Nature, patriarchal systems of thought, in our educational systems adherence to rationalism and materialism to the exclusion of intuitive appreciations of the natural world, and to centralised and decentralised economic systems that view Nature as a commodity, a thing to be used or controlled.  The difference is that now we have the technological capability to cause massive change, after all, one could argue that carbon emissions were an unconscious experiment in geoengineering.

A large failing behind some of these research ideas is an understanding of ecology and interdependence. Life on this planet does not depend upon one factor, and we cannot simply treat our species as a separate system from this delicate and intricate web of interaction. Life has evolved over 3.5 billions of years with a vast multitude of its own experiments and optimisations that we ourselves are part. To alter one parameter is to change all the rest.

The key problem is one of relationship. If we understood that solutions require working with Nature, rather than against, this type of thinking would not arise. Let us not force the hand that feeds us.

This article can be found also at SALT magazine.

world bubble

Understanding Trees

Three hundred and seventy years ago a Belgian alchemist and physician was exploring ideas that there were other gases in the atmosphere, as well as the idea that the substance which makes up plants and trees did not come from the soil, which was thought at the time.

van Helmond

Jan Baptist van Helmont (1580 – 1644)

This man, Jan Baptista van Helmont, was the first to do these experiments on a willow tree in a pot over a 5 year period. He took accurate readings of the mass of the soil, the tree and the water added, using modern experimental ideas of science introduced by the likes of Galileo, William Harvey and Francis Bacon.

Weeping Willow

Weeping Willow

After 5 years he checked the mass of the soil and found it had not changed by much, and so it could not explain the mass of the willow tree. He therefore assumed incorrectly that all the mass came from the water added during its lifespan. It was only until 160 years had passed that Nicolas-Théodore de Saussure, a Swiss chemist, repeated van Helmont’s experiments along with analysis of the gases given off by the tree, and concluded that carbon dioxide contributed significantly in explaining the mass of the tree.

Wood cross section

From carbon dioxide to carbon in wood…

Today we know that about 98 % of the mass of a tree is made up of carbon, hydrogen, oxygen, nitrogen, phosphorous and sulphur, with the first three of those elements contributing mostly to its mass (dried wood is about 50 % carbon).

What this means, is that simply by using a small amount of surface area of arable land, and by adding water, we have a mechanism of removing carbon from the atmosphere. And this resulting creation not only provides a habitat for a multitude of life ranging from the microscopic to larger mammals, it also provides us with oxygen and is most pleasant in appearance. And I have not even mentioned fruit trees here.

I challenge you to think of a similar mechanism which can remove carbon from the atmosphere with the same cost, efficiency and environmental impact.

A Solution in our Midst

The atmospheric carbon dioxide (CO2) concentration, as reported by the Mauna Loa Observatory in Hawaii, was recorded at 395.5 ppm1 (parts per million) as of January 2013. This value is consistent with the upward trend as measured since 1959 from this observatory. The maximum value Earth’s atmosphere should have, if we wish to sustain life on this planet in its current form, is 350 ppm2. Not only do we have much work to get there, but we first have to stop the rising trend which is moving in the opposite direction.

Latest CO2 Trends (National Oceanic and Atmospheric Administration - US Dept. of Commerce)

Latest CO2 Trends (National Oceanic and Atmospheric Administration – US Dept. of Commerce)

Copenhagen climate negotiators in 2009 argued to keep the increase in average global temperature below 3.6 °F or 2 °C. This target of low ambition would lead to a different planet, one with an ice-free Arctic and sea level rises of many metres3,4, affecting hundreds of millions of people and the planet’s fauna and flora. Currently, The Marshalls, Kiribati, and Tuvalu islands are already feeling the effects of rising sea levels. If we continue business as usual we are looking at an increase of 5.4 °F or 3 °C, which would result in a collapse of the Amazon ecosystem, sea levels 25 metres higher and huge terrestrial areas exposed to permanent drought. The Earth will be vastly different.

Already Kiribati is suffering from sea level rise. They are currently negotiating with Fiji to by land for relocation. (Ciril Jazbec)

Already Kiribati is suffering from sea level rise. They are currently negotiating with Fiji to buy land for relocation. (Ciril Jazbec)

As is often the case, governments are slow to act, and even when the facts are simple and the case is clear, presidents and prime ministers have been fearful about affecting their re-election.  A broader and more honest response is required. Such a response requires first understanding the gravity of the situation and then acting, or creating incentives for solutions. Richard Branson has done exactly that with the setting up of the Carbon War Room as well as creating the Virgin Earth Challenge where a $25 million prize will be awarded for an economically viable and environmentally sustainable way to remove greenhouse gases from the atmosphere. Current finalists have been announced.

A $25 million prize

A $25 million prize

Such a contest is to be welcomed and the technologies celebrated, but perhaps there is a simpler technology in our midst. One that is so familiar that we take it for granted, yet when absent, its lack is felt in barren landscapes and concrete vistas. I speak here of the tree. The first tree appeared in the mid-Devonian period 385 million years ago. As forests rose in the latter part of this period the Earth’s CO2 concentration was reduced which resulted in a cooling of the planet. We thus know this technology works.


Trees can be large and small, narrow and broad. But no matter their size, the carbon content of woody matter (trunk, branches and roots) is about 50 %.  Researchers at Ecometrica derived a general equation for the mass of a tree based on its dimensions and calculated that a mature sycamore of height 12 m contains one ton of carbon. And this ton of carbon would have locked up 3.67 tons of CO2 from the atmosphere in a form pleasing to the eye and of much use to fauna and ecosystems.  Simple is beautiful.



  1. Mauna Loa Observatory Data
  2. Hansen et. al. (2008). Target Atmospheric CO2: Where Should Humanity Aim?
  3. Mark Fischetti. 2-Degree Global Warming Limit Is Called a “Prescription for Disaster”. Scientific American Dec 2011.
  4. Robinson et. al. (2012). Multistability and critical thresholds of the Greenland ice sheet. Nature Climate Change 2, 429 – 432 

The Natural Powerhouse

While humans have proudly developed their own power sources using mostly fossil fuels, uranium and rivers, photosynthesis in nature captures approximately 6 times as much energy consumed by modern civilisation. This capture rate is about 100 terawatts, gained from our closest star, the Sun.

The Sun

Trees love the Sun (Soho Extreme Ultraviolet Imaging Telescope, EIT Consortium)

How is this done? The leaves of trees and plants have tiny organelles containing chlorophyll which absorb mostly blue and red light, so we see them as green. An idea of this global activity can be observed in the world map showing concentration of chlorophyll in the sea (from phytoplankton), and vegetation concentration on land.

Chlorophyll Map

Chlorophyll Map of Earth. Sea shows chlorophyll concentration and land shows relative vegetation index.

This energy captured promotes, through the production of electrons, the reaction between carbon dioxide from the atmosphere and water to produce sugar and oxygen. In trees, the water comes from the roots transported via the xylem (see previous blog) and reacts with carbon dioxide which enters through tiny holes in the leaf, or stomata (see pic).

Tomato leaf Stoma

Leaf Stoma

The sugars produced are then transported via the phloem to the roots. The basic reaction is 6CO2 + 6H2O –> C6H12O6 (sugar) + 6O2, meaning for each part of carbon dioxide reacting, an equivalent amount of oxygen is produced.

In this way a mature tree can provide enough oxygen for 2 people to live per year, while in total, photosynthetic organisms convert about 100-115 petagrams (15 zero’s!) of carbon into biomass per year.

The competition for light in the forest is intense and sometimes trees are growing too close to each other, thereby undermining each other’s health. Shade tolerance is therefore a key competitive advantage. However, with human activity, competition for light is the least of a tree’s worries. Trees have evolved at different latitudes in different ways to capture this light. At the equator where the sun is overhead all year round, trees have broad canopies. While at higher latitudes trees generally have narrow and extended crowns to capture light at lower angles, e.g. conifers.

There is thus perhaps a simple way of being more conscious of trees and having them in our awareness, if on a sunny day we can occasionally be mindful when we enjoy a deep, luxurious breath of air, and think about that oxygen that sustains us.