After decades of study based on thousands of years of data, the verdict is in: The earth is getting hotter. Considering average global temperatures since 1865, 20 out of 21 of the hottest years
measured have occurred in the last 25 years! Most of these increases are due to carbon dioxide (CO2) which is known to trap heat in the earth’s atmosphere. Over a period of 650,000 years, levels of COs
closely match deviations from the earth’s mean temperature, clearly showing both ice ages, heat waves and today’s mild climate.
At no time in these 650 centuries up to the industrial age have COs levels been above 300 parts per million (ppm). Today, COs levels stand at about 370 ppm, and are rising at about 1.8 – 2.6 ppm per
year. These levels are projected to reach 450 ppm (or more) by the year 2050. Considering that ice ages occur when CO2 levels are at 160 ppm (a drop of 140 from CO2 levels related to recent mild
temperatures) what will our climate be with this projected increase of 150 ppm? Note that in 1999, it was projected that 1,442 new coal-fired power plants will be built by the year 2030, and that in 2002,
coal contributed 41% of the CO2 released into the atmosphere. Note also that CO2 remains in the atmosphere for about a century. We are rapidly putting the earth on a path that has never occurred
before, and with unknown, but most likely dire, consequences.
Is Lake Merritt getting warmer? Essentially, the available data set is not adequate to determine this. A regression (statistical) analysis of most of the known data (twelve months in 1972-3 and sporadic data
from 1990 to the present – with several gaps) indicates that surface temperatures may have actually dropped by a few degrees F. in the last few decades. But considering the limited data and numerous
gaps, the record is too limited to be certain. In addition, changes in operation of the tide gates during these years and Lake-wide dredging in the mid ‘80’s have undoubtedly impacted Lake temperatures.
Also, methods used to measure and record data over the years have been quite variable. It is interesting to note however, that minimum temperatures from the mid 1990’s and 2005 do indicate a
considerable warming trend, and that the oceans in general have been warming.
What will happen to Lake Merritt as the earth gets hotter? Global warming manifests itself in many ways, not the least of which is flooding due to changed rainfall patterns and sea level rise. Our Lake however, is protected from flooding (to a certain point) by tide gates and pumps. More common storms will not cause the Lake to flood. But if, as many predict, COs levels continue to increase and
either the Greenland ice sheet melts (about 1/3 of it is melting now) or the west Antarctic ice shelf melts (ocean temperatures under it have warmed) or half of each melts, sea level rise would be
between 18 and 20 feet, and the Lake would be only a few feet above sea level. By the way, the entire City of Alameda would be under water. The Lake would not quite be joined to the Bay, but the tide gates and pump station might be under water (as well as Jack London Square and much of the Port).
What is more certain is that we will see a change in the distribution of plants, animals and people, as has been already documented elsewhere. Formal monitoring of the Lake does not include life forms, but we did notice wire weed for the first time a few years ago, and a very large decrease in spring algae and summer widgeon grass during the last three years. As the Lake warms, red tide plankton blooms, which thrive in hotter water, will become more prevalent. It is also likely that disease vectors will increase, the Lake will become more acidic (as have the oceans in general due to global warming) and air temperatures will be much hotter. A more acid Lake would reduce the prevalence of animals that build calcium carbonate houses, such as our tubeworms, clams and mussels.
An increase in rainfall is also possible since warmer air holds more moisture. This would mean a less salty Lake, and more urban runoff. Combined with increased tide gate closures for flood control, this
will cause (unless a mixing system is installed) more and longer periods of stratification, leading to more and longer periods of very low oxygen levels, especially in the bottom layers. An increase in tide gate closures has already been documented along the Thames River in London where between 1990 and 1999, rising sea levels caused the gates to be closed more than twice as many times per year compared to the period from 1931 to1990. Global warming is not a prediction, it has started.
Trees, Plants are Great, But the Real Action is Underground
By Ron Sullivan, Special to the Planet (08-01-06)
In some ways, we humans are educating ourselves about the planet that sustains us the way the owner of a cranky old car educates herself about how cars work: We learn about systems and parts when they break down and we’re forced to figure out why. Partly that’s a matter of perceived urgency that gets grants written and funding done—“pure” research is a delicious notion, but it’s rare that anyone can get the time, facilities, and support to study a matter just because we all get intrigued by it.
Studies aside, there’s the matter of which things get the attention of the broader public. That attention eventually drives some funding, of course, from foundations with close oversight from nonspecialists. And sometimes several foci come together, and something pops up that nobody had imagined. Sometimes that something is the importance of a known fact or substance, importance that is greater than anyone had assumed.
Lately there’s been media hand waving and even actual information about carbon sequestration. Five, 10 years ago, how many of us had ever heard the phrase, let alone known what it is or why it matters? It matters because carbon in the air, combined with oxygen as carbon dioxide, is a “greenhouse gas”; that is, when there’s lots of it in the upper atmosphere, it helps create that greenhouse effect that’s destabilizing the weather systems we’ve had for a long time, making the world’s air a bit warmer by trapping solar heat that used to escape. It doesn’t take much, just a few degrees, to get glaciers and polar ice caps melting and ocean temperatures rising and currents changing, including upwellings that feed sea life (and then us) and surface changes that make storms stronger.
Carbon sequestration is an ecosystem service (another new term: the life-support the world gives us) that helps put the brakes on this career. Plants, in particular, make themselves out of elements including carbon. Remember that thing about how they “inhale” carbon dioxide and “exhale” oxygen? They keep that carbon atom and make it into their flesh.
As long as they live, they keep the carbon they accumulate out of the air. Imagine how much carbon is in a hundred-foot tree, or an acre of grassland or chaparral. When they die and decay, or burn, that carbon goes back up in real or virtual smoke. When trees are cut down, they stop working, even if the carbon in the lumber stays there for (optimistically) a few centuries. The waste, the sawdust, the trampled understory, starts decaying then and there.
But there’s more to the forest than the trees.
Under all that green stuff, way down in the dirt, there’s serious and complicated action going on. Roots are growing, absorbing nutrients from the soil, engaging in the dark half of that great dance of making. Roots are permeable, and so is the whole substance of the forest, or the field, or wherever plants grow.
Trees and many other plants, when we look closely, aren’t isolated, aren’t independent, aren’t even quite separate entities. They absorb what they need from the soil with the help of the mycorrhizal network, the web of fungi under the surface that lives in symbiosis with many plants. People who garden with native plants and who keep bonsai are finding that a bit of soil from a plant’s original home might inoculate its new one with the right organisms to help the plant flourish.
Mycorrhizae are performing another ecosystem service that has only recently come to light. The USDA published a report by Don Comis on work by Sara F. Wright and Kristine A. Nichols that suggests that a substance called glomalin, discovered by Wright in 1996, does indeed glom onto quite a lot of carbon—27 percent of the carbon in soil. It binds organic matter to mineral particles in soil. It also forms soil clumps—aggregates—that improve soil structure and keep other soil carbon from escaping.
Glomalin is produced by arbuscular mycorrhizal fungi (order Glomales, hence the name) on plants’ roots, from carbon they trade for other nutrients and water. The fungi produce glomalin, apparently to seal themselves and gain enough rigidity to carry the stuff across the air spaces between soil particles. The fungi grow only on the newest root tips; the glomalin sloughs off the dissolving older hyphae and stays in the soil for seven to 42 years.
There are ways like no-till farming to encourage glomalin production, but keeping a piece of ecosystem intact in its original form seems to keep the stuff in the soil in greatest amounts. Yet another reason to keep our collective hands off, to avoid breaking what we don’t understand well enough to fix.
See the forest for the trees? A lot of “ecosystem services” take place underground, out of sight.
Injection of Sulfur in the Atmosphere an Option to Fight Global Warming
In a study to be published in the August issue of Climate Change, Nobel laureate Paul Crutzen of the Max Planck Institute for Chemistry in Germany and the Scripps Institution of Oceanography in the University of Californi at San Diego, says that with the apparent lack of political will to curb man-made greenhouse gases (GHGs), cooling down the atmosphere through sulfur injection is an option worth serious consideration. Dr. Crutzen said, “Given the grossly disappointing international political response to the required greenhouse gas emissions,…research on the feasibility and
environmental consequences of climate engineering of the kind presented in this paper, which might need to be deployed in future, should not be tabooed.”
Sulfur particles in the atmosphere have a cooling effect as they reflect more sunlight back into the space. Dr. Crutzen, winner of the 1995 Nobel Prize in Chemistry, argues that this effect could offset the warming effect of GHGs. His idea is based on the 1991 eruption of Mount Pinatubo, which after ejecting sulfur in the atmosphere, global average temperature dropped 0.5°C one year later. Dr. Crutzen’s method employs balloons to carry sulfur
into the stratosphere, then using artillery guns to release it.
The “albedo enhancement” would take place six months in the atmosphere after the injection of sulfur. The sulfur particles could stay in the stratosphere for up to two years. Although Dr. Crutzen’s proposal is being taken seriously by many scientists, he warned that his proposal is just for emergency purposes. Dr. Crutzen said, “Importantly, its possibility should not be used to justify inadequate climate policies, but merely to create a possibility to combat potentially drastic climate heating,…The very best would be if emissions of the greenhouse gases could be reduced. Currently,
this looks like a pious wish.”