I have been reading several papers about the role of CO2 in plant ecology with regard to global climate. I’ve written to the several scientists in this post posing the following ideas. Hoping for some conversation to emerge.

Dear Colleagues,

I am working on a model of climate that is a plant ecologists model first and a climate physicists model second. It seems to me that plant life on this planet is in control of CO2 to a very great extent. Climate physics models on the other hand seem to relegate plant life and its potent action on CO2 as but a tiny factor. Indeed some great errors have been made by the climate physicists in this regard.

I wonder if you are aware of or might have considered the following ideas on how plant ecology is driving CO2 and climate.

Amazon Rainforest Biomass

I was reading an account of the work Sassan Saatchi of JPL on estimating the amount of CO2e that is accounted for by the Amazon rainforest.  He is quoted as pegging the Amazon to be holding on to 86 billion tonnes of CO2e in standing biomass.

I am struck at a connection with this “Amazon rainforest unit of CO2 measure” with reported observations of declining ocean biomass and it’s CO2e.

Worm et al have reported another pegging of an ecosystems CO2, the ocean plankton pasture ecosystem. In this case they note that since the 1950’s the ocean plankton pastures have lost the equivalent of an Amazon rainforest worth of biomass in each five year period.

This adds up to 12 Amazons worth of standing biomass gone from the oceans in the last 60 years. That in turn adds up, using Amazon CO2e numbers, to be 1032 billion tonnes, a trillion tonnes, of CO2 not being managed by the formerly healthy ocean plankton pastures.

This is an astonishing number. If we were to take the annual anthropogenic surplus CO2 accumulating in global systems at 10 billion tonnes per year the loss of ocean management of said trillion tonnes accounts for at least a doubling effect of CO2e in all of its roles in recent times. Surely this is a major factor in the physics, chemistry, and more importantly the ecology of CO2.

As a plant ecologist I am most concerned with the role of CO2 with plant life. I believe that the ecological effects of CO2 have been pushed far into the subtext of CO2 as a factor in climate change and global warming. However CO2 is so potent with regard to plant life and plants on this world are key to creating and sustaining the environment within which they live that somehow there is something dreadfully wrong with all of the focus on CO2 as merely a climate physics issue.

Plants Produce Water Vapour

Very recently a monumental paper was published with very little notice in Nature. A young grad student in New Mexico (Scott Jasechko et al ) studied the role of high and rising CO2 on plant transpiration and on the role of plant transpiration of atmospheric water vapour. His work shows that plants are responsible for contributing 60% of all water vapour to the atmosphere! Evaporation only contributes 40%! There are corroborating reports to support this.

In this time of high and rising CO2 plant efficiency with regard to gas exchange has been greatly enhanced by high and rising CO2. This has resulted in dramatic slowing of transpired water vapour. With plants are now transpiring 10%-20% less water vapour.

Amazon Droughts

This reduction of atmospheric water vapour, the major GHG, has to be having a negative feedback effect on global warming. It surely also is having a large effect on resulting in the drying of rainforest ecosystems.

But far worse the CO2 benefit to terrestrial vegetation is being seen as dramatic planetary greening as dryland vegetation, the largest plant ecosystems on this planet, are greatly benefiting from the savings of transpired water which is promoting more plant growth. We call more plant growth and longer growth “good ground cover” in the world of dryland ecosystem management. This good ground cover is being seen in dramatic reductions of topsoil and dust blowing away in the wind from these drylands.

That diminished dust in the wind is the link to the collapse of ocean plankton pastures at the observed rate of loss of an Amazon Rainforest of biomass in each five year time span.

Declining Ocean Plant Life By Ocean Basin
click to enlarge

As the ocean plants depend on dust in the wind for vital mineral micronutrients they are collapsing as the dust becomes ever scarcer.

Those ocean plankton pastures and the trillion tonnes of CO2 they are no longer managing ought to be entering the models on global CO2 as the largest factor and not in their present role of not being in the models at all or only in some very minor role.

A last paper in this collection comes from a Finish group and speaks to how forest aerosols are important in cloud formation.    I loved the metaphor one scientist in that group used saying that we all know about forest aerosols as they are “the smell of the forest.”  I have spent much of my life working as a plant ecologist in forests and know those smells very well. It seems that forest smells have a significant role in weather!

I am hoping that you might give this some consideration and perhaps you have some thoughts on how the ideas I am presenting here might be put in front of people with influence on CO2 and climate policy.

The good news is that the replenishment and restoration of ocean plankton pastures to the condition of health and abundance that they were in in 1950 is very workable and affordable. Such work could restore the oceans and buy the world a lot of time on the CO2 crisis. It Just Works!