Contributed by Dr. Rob Moir
It was more than fireworks heating up the sky during the 2023 Independence Day celebrations.
July 3rd was the hottest day recorded as a global average of temperatures taken at hundreds of sites worldwide. The worldwide average for that day was 62.62 degrees Fahrenheit. The record stood one day until July 4th, which was even hotter at 62.92 degrees. The previous record was 62.46 degrees, measured on August 14, 2016.
The third-place record was set despite the many parts per million increases in atmospheric CO2 driving climate change because there was also an El Nino in the Pacific Ocean off California. An El Nino is an ocean effect when warm water is along the coast instead of offshore. This is one example of how the ocean determines the climate. The ocean is so complex that we cannot predict how long the warm El Nino will stay along the continent or when the El Nino will draw back, releasing cold upwelling water to the surface. Every year we are spectators to what the ocean is doing.
The Arctic Ocean also influences global average temperatures. The sea ice in the Arctic Ocean has shrunk to cover less than a third of the surface, instead of the historic nearly two-thirds covered ocean. Most of the Arctic freezes over with the onset of winter in October. There is an immense increase in the amount of sea ice forming. Today’s open Arctic Ocean has more than twice as much sea ice formed. At 32 degrees Fahrenheit, water molecules link up to form a solid, ice. Because temperatures must be colder before the freezing water could include salt, the brine is excluded, and the sea ice consists of fresh water.
The cold, briny water next to the ice is the densest water in the world. It sinks, and cold, nutrient-rich Arctic water accelerates the thermohaline circulation of the world’s ocean currents. Thus, in 2011 the Gulf Stream meandered further up onto the continental shelf towards Rhode Island, and in 2007, the Gulf Stream surfaced to warm Svalbard. More water is entering the Arctic Ocean from the Atlantic to increase the summer sea ice’s melt further. This is why measuring air temperatures in the Arctic could not explain the rapidity of sea ice melt. The power and planetary influence of the ocean were underestimated if considered at all.
In 1896, Svante Arrenhius, Greta Thunberg’s great, great grandparent’s second cousin, calculated that increasing atmospheric carbon dioxide would increase and result in a 0.2 degree C rise in global temperatures. He was not alarmed because he understood that it would require people to alter the hydrological cycle for this to happen. Something he thought impossible given the immensity of global systems.
George Perkins Marsh understood how we were altering global water cycles. In his book Man and Nature, or Physical Geography as Modified by Human Action (1864), Marsh documented how humanity had disrupted the hydrological cycle for 8,000 years. It began with agriculture that worked the land unnaturally. First, the furrow and later, the plow opened the soil to gas out water vapor and carbon. Green landscapes died by people clearing, burning, furrowing, fertilizing, irrigating, fallowing, and generally messing with nature. Marsh documented the aridification and spread of deserts from Morocco across the Sahara, the Middle East across the Steppes to Mongolia. Our agricultural practices killed soils and stopped plant-driven local water cycles. During the Dust Bowl, Franklin D Roosevelt summed it up, saying, “A nation without soil cannot survive.”
The problem is that atmospheric carbon (CO2) has risen from 350 parts per million or 700 billion tons of global carbon to 420 parts per million, 800 billion tons. To restore the planet to 350 ppm, we must achieve net zero emissions and then draw down an additional 100 billion tons of carbon.
Where is the carbon to go? Above-ground global biomass is about 564 billion tons of carbon. A 20% increase in biomass is quixotic. Despite being a small percentage of the Earth’s surface area, soil holds 2,800 billion tons of organic carbon, about three and a half times the carbon in the atmosphere. One hundred billion tons of carbon is less than 4% of soil’s organic carbon.
Soil is alive and dirt is not. More microbes are found in one cubic meter of soil than people living on Earth. Until recently, we only concerned ourselves with the top six inches. Meanwhile, plant roots were reaching down eight feet or more. As a result, we know more about the ocean, which is only a little of all there is to know, than we do about the rhizosphere, the realm of soil.
Soil is one of the few places not powered by the sun. Instead, plants take sunlight, carbon dioxide, and water to manufacture carbohydrates (liquid carbon). Carbohydrates are the only substance in the universe that naturally defies entropy and can be oxidized to give energy. Life reverses entropy with carbohydrates and concentrates power up food pyramids to the extent that a pound of swordfish, seven trophic levels up, results from the food energy from 100,000 pounds of phytoplankton.
Soil is living like flesh. Cut it with a shovel to sever the fungal networks binding the soil together. The transport of carbohydrates from plants is disrupted, as is the flow of nutrients and minerals prepared by bacteria to plants. The opened soil bleeds greenhouse gasses out into the air.
Plants are set in their carbohydrate production ways to always direct the same carbon proportion to biomass and soil. Most plants retain two-thirds of the liquid carbon for biomass. One-third is fed to the soil as root exudates. Prairie grasses, salt marsh, sea grasses, and even lawn grasses are the soil carbon champions. Grasses always direct about half of the carbon to fungi and bacteria in the ground. Grasses create one ton of root exudate and one ton of biomass by drawing down 7.3 tons of CO2. An established lawn (not disrupted by frequent fertilizing) in the best weather can build an inch of soil in a year. With four inches of soil, the lawn can swell to hold seven inches of rainwater. The more water in the soil, the more plants will grow, and the more carbon dioxide is drawn out of the air.
Plants regulate microclimates by opening stomata to release water vapor. When hot, plants release water vapor that evaporates to cool the immediate surroundings. This is why standing beneath a leafy tree on a hot day is cooler than standing in the shade of an awning. Conversely, at the coldest time of day, before dawn, plants actively release water that condenses and forms dew to warm the area.
Water and bacteria released by plants rise into the air, while water vapor will come together around bacteria to form clouds. A million bacteria with vapor are needed to form a raindrop with sufficient weight to fall to the ground. (Water vapor around dust particles is statically charged and repels to form a haze that is too light to fall.)
Land covered by plants will reradiate about 20% of the heat energy from the sun. A patch of exposed dirt or an impervious surface such as asphalt warms the planet by reradiating about 60% of the energy. Water transpired by plants rises to form clouds that both release and capture thermal energy. White puffy cumulus clouds reflect light and further cool the planet. These clouds once covered more than 50% of the Earth. Today, clouds cover less than 50%.
Each of us can make a difference by stewarding the growth of plants. We may cover cement patios and steps with potted plants and raised beds on hard surfaces. Turning a hardscape to green decreases reradiated heat by three times. Support your local water cycles and enjoy more clouds. Deeping soils hold more water that protects homes from more frequent heavy rains.
High cirrus clouds retain and radiate much less thermal energy into space. This gives water vapour the distinction of being the world’s largest greenhouse gas, weighing in at 1,000 times the concentration of carbon dioxide. Fortunately, we need just a few percentage points more cumulus clouds to swing the balance to cool the planet.
With more water held in the ground, plants draw down more carbon to manufacture more organic carbon. Organic carbon can go in one of two directions. Carbon can either burn/oxidize or be stored in soil and sediments. Soils may undergo a chemical transformation to form hummus, where carbon is held for thousands of years.
We must increase soil carbon by 4% and planetary reradiation with more clouds and less carbon dioxide by 2% to right the wrongs. Less than 20% of the world’s lands are covered by soil, and around 40% are deserts and degraded soils. This does not include urban areas. With incremental increases in more plants, especially grasses, healthier soils, and restored local water cycles, we will live more comfortably while restoring the climate without unwanted July 4th climate fireworks.
Dr. Rob Moir is a nationally-recognized and award-winning environmentalist. He is president & executive director of Cambridge, MA-based Ocean River Institute, a nonprofit providing expertise, services, resources, and information unavailable on a localized level to support the efforts of environmental organizations. Please visit www.oceanriver.org for more information
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- Of Mousy & Elephantine Cycles, Managing The Climate Crisis After Glasgow COP26
- Melting Greenland Ice Sheet, Sea Ice Formation, and the Flow of The Gulf Stream
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