Monday, September 5, 2022

Photosynthesis: A love song. Part II. Carbon fixation, C02 and global warming

 




 

Photosynthesis: A Love Song

Lyrics by Bette Korber, sung to the old Irish melody Samhradh, Samhradh

 

In part II, I shift from photosynthesis to carbon cycles and global warming, the importance of preserving forests if we are to preserve life as we know it, and my political perspective on past missed opportunities to mitigate global warming and current opportunities for hope. 

 

Photosynthesis is untainted by politics; I, on the other hand, am not.


Greenhouse gases and carbon cycles

 

The cycles of photosynthesis spin again and again, and the earth has passed through eons in relative balance: life, water, carbon, light. The carbon “fixed” through photosynthesis is transformed into to the web of life, and we have evolved as part of this balance and rhythm. Much of the remains of life’s past on the planet is tucked away into earth, millions of years of life’s chemical energy is pressed by time and the weight of the Sea and the Earth into coal and oil just under the surface of the planet. And, of course, we have figured out how to tap that energy, bend it to our will. We are comfortably warm in winter, cool in the summer; we push back the darkness of night in our homes filled with light; we move with dazzling speed in our cars, trains, and airplanes; we create vast monocultures of farmland to feed billions of us. To do this, we are burning coal and oil too fast, pouring millions of years of life’s history of carbon capture into the sky all at once; together humanity is pulling the earth and sky out of balance. In just the past 64 years, over my short lifetime and in the blink of a geologic eye, we have pushed carbon levels in the atmosphere to much higher levels then have been seen in the 800,000 years before (NASA, the Relentless Rise of Carbon Dioxide). Tiny pockets of air locked in ancient ice can tell us the truth of the history of the atmosphere. Although we are now entering uncharted territory, we understand the science of our planet home well enough to anticipate the consequences of so much carbon in the atmosphere.

 


NASA graphic showing us the levels of CO2 in the air in the last 800,000 years

 

 

Here is what greenhouse gases do: The sun’s energy warms the earth during the day, and the incoming sunlight moves past the C02 and water in the atmosphere, to warm the earth.  The earth radiates this warmth back out, but transformed so that C02 and other greenhouse gases can absorb some of it on its way out from our planet. This is natural, and keeps our Earth above freezing, giving us the global climate we are familiar with. But greenhouse gases are increasing;  CO2 and methane are released from the burning and burning and burning of the coal and oil that were once safely stored in the Earth. More CO2 will absorb more of that heat, which will warm up our atmosphere, and radiate some of that warmth back towards the planet. 

 

Charts from NOAA, the National Oceanic and Atmospheric Administration, show the monthly mean carbon dioxide measured at Mauna Loa Observatory, Hawaii; the data from Mauna Loa provide the longest record of direct measurements of CO2 in the atmosphere, a program started in 1958. These focus in on recent years, on just that crazy terrifying vertical line on the far right in the figure above from NASA. The red lines show monthly mean CO2 levels, the black lines the same, but corrected for seasonal cycles. When they started the measurements in 1958, we were already above the all of the peaks due to natural fluctuation of CO2 in the last 800,000 years of the Earth’s history.

Mean monthly CO2 atmospheric concentrations over time at the Mauna Loa Observatory, in the last 5 years (left), and over my lifetime, since 1958 (right).


 
 
Looking to the deep past, we know that when temperatures have changed abruptly across our planet, mass extinctions have accompanied the change.  Our dear old mother Earth is 4.5 billion years old just now, she has been circling the sun for about 1/3 of the history of the universe, so for the Earth, even a few million years could be considered “abrupt.” But humankind has brought a whole new level of abruptness: 70 years. We are beginning to feel the consequences of the trouble we have stirred up because we have become ever more adept at pulling the oil, gas, and coal from the Earth. The storms, the droughts, the severe heat waves, the fires and the flooding, the rising seas, the melting ice caps, all are leaving great suffering in their wake, and are vivid and constant warnings of more to come.

 

If we want to leave our children a habitable home, the time to act is now, and we need all hands (and branches) on deck; forests and trees are a part of the solution. Forests remove CO2 from the atmosphere through photosynthesis, and we need a global resolve to preserve the Earth’s forest canopies to enable these glorious, perfect, beautiful, precious-beyond-measure "carbon sinks" to keep at their task. Remarkably, as CO2 increases the plants and forests of the world increase their CO2 uptake in response, tempering for at least a little while the worst that climate change has in store, giving us more time to make a difference. Nurturing these natural solutions to climate change mitigation has to be a part of the solution, and these natural solutions to global warming simultaneously provide natural habitat to temper the loss of so many plants and animals to extinction. It is urgent that we put aside our past inclination to put short-term economics and the wealth of individuals ahead of protecting nature and our place in it.

 

We need the best scientific information to understand how to live more gently on the Earth despite our numbers.  Thanks to satellite data and ground measurements, we are getting much better at monitoring the world's forests, their health and ability to take in carbon, and defining precisely where deforestation and fires forests are causing us to lose ground. We are beginning to understand the importance of maintaining complexity in forests for their preservation and sustainable use, and applying this knowledge in forestry. So we are getting more able to heal what was lost and to track and understand what is being taken.

 

Through the Paris Agreement, initiated in 2016, nations made legally binding promises to act in a globally coordinated effort to prevent extreme climate warming. It is up to the citizens of the world to bend the will of our nations to follow through on our agreements. We are bound by these accords to switch to clean energy, to share technology, to support those who are suffering most under the impact of our changing climate, and to protect natural carbon-sinks (the forests of the world fall under this protection). In 2021, the Glasgow Climate Pact brought 200 countries together to advance our global response to climate change, to recharge the integrated international efforts agreed upon in Paris, and to bring a more limited level of global warming, 1.5° C, into the realm of the possible. We renewed our promise to help the world adapt to the climate change disasters that have already started and to share resources with those who are most severely impacted.  In the US, at this point in time, climate change is still only rarely a part of the political conversation; at some point the extreme weather we are already experiencing will compel us to care, but the earlier we come to this awareness and concern the better for the Earth. Despite our differences in understanding the severity of this problem, our nation has finally managed to get legislation passed, the Inflation Reduction Act, to enable progress; we must build on this momentum. 


Political swings and lost opportunities

 

When we think of global warming and greenhouse gases I think many of us forget how long we have understood the looming problem. I grew up in the 60's and 70's; it was part of the discourse then, and there have been many lost opportunities. I remember when Jimmy Carter founded the Solar Energy Research Institute (SERI) in 1977, to explore renewable energy alternatives to fossil fuels with the goal of 20% of the US’s energy needs being met by renewable energy by the turn of the century. In a fine gesture, Carter put up solar panels to heat the water in the white house in June of 1979. My mother was in step with him, and wanted to support this fledgling industry and to support a hope for the future. We had solar panels on our house as soon as she could afford them, encouraged by the tax breaks that were offered at time. 

 

Ronald Reagan took down Carter’s White House solar panels in 1986, but Reagan’s destructive sweep went much deeper than that small act. He took our nation off from the path Carter had carefully laid out, taking us away from a trajectory where we could have become a world leader in renewable energy, and in doing this he changed the course of global warming. As noted by David Biello in a brief history of Carter's solar energy intentions, “By 1986, the Reagan administration had gutted the research and development budgets for renewable energy at the then-fledgling U.S. Department of Energy (DoE) and eliminated tax breaks for the deployment of wind turbines and solar technologies—recommitting the nation to reliance on cheap but polluting fossil fuels, often from foreign suppliers.” Little SERI was downsized, precious decades were lost. SERI gradually recovered, and morphed into the National Renewable Energy Laboratory (NREL). Key advances in solar panel technology that are incorporated in the working solar farms today came out of President Carter's legacy. Other tragic steps backwards for the US were when Al Gore, with his deep understanding of the importance of responding to climate science, lost the election to George W. Bush in the electoral college vote and Supreme Court decision, despite having won the popular vote by over half a million votes. In more recent times, President Obama was making real climate progress in his 2nd term, but President Trump systematically dismantled Obama's legacy as soon as he entered office. This set us back in a critical time when climate change is of the greatest urgency. Trump’s actions included backing out of our commitment to the Paris Agreement, reversing Obama-era rulings to cut back greenhouse gas emissions, opening up public lands to more fracking, and increasing offshore drilling (this proved to be so unpopular he had to backtrack). Trump also illegally pressed forward on the  Keystone XL Pipeline which Obama blocked, Trump initiated, and Biden revoked. The Dakota Access Pipeline (DAPL) was blocked by Obama blocked in response to an inspiring and brave resistance movement led by the Standing Rock Sioux; Trump fast-tracked building it as soon as he entered the Oval Office; under Biden is still operational while under further environmental review. DAPL not only increases our dependency on oil, it continues to put our waters, in particular the critical lifeline of the Missouri river, at grave risk.



There were huge set backs to our response to global warming during Trump's presidency; the extent of the damage caused by his actions is profound. We cannot afford to let this happen again. It is the critical issue of our times.

 

A personal regret

 

When I entered graduate school in 1981, not only was I enchanted by photosynthesis, but I wanted to work defend our planet from the prospects of climate change as we continued to scale up our burning of fossil fuels. I had a dream of working on bio-inspired solar energy converters that could be used to transition us away from fossil fuels. Melvin Calvin, the man whose discoveries help bring us the understanding of photosynthesis, was at Berkeley and was still working on such concepts, but he had just retired. I got to meet him, and was utterly charmed, but I had missed the opportunity to work for him by a few years. The other person I knew who was working on such ideas was John Hopfield, at Caltech. So Caltech is where I choose to go to graduate school, and Hopfield had expressed an interest in taking me on as a student. When I arrived at Caltech, however, I was pushed into more experimental biology research by Norman Davidson, the man who was assigned to be my initial advisor, and I ultimately wound up working in immunology, a different field altogether. Although our immune systems are very beautiful, and understanding virus/immune interactions and evolution has given me interesting life’s work, I still grieve that switch. If there is one major regret I have in life, it was letting Norman force my path into a field he felt was better suited to women, rather than having the fortitude to follow my own ambition. One of my (male) classmates, a good man who became a friend, stepped into the project I had wanted to work on, and some solid work resulted. And happily, the basic notion of mimicking the leaf to fix carbon and create fuel is a lively area of research today, and good things may come of it.

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