The SeaWiFS instrument aboard the Seastar satellite has been collecting ocean data since 1997. By monitoring the color of reflected light via satellite, scientists can determine how successfully plant life is photosynthesizing. A measurement of photosynthesis is essentially a measurement of successful growth, and growth means successful use of ambient carbon. This animation shows an average of 10 years worth of SeaWiFS data. Dark blue represents warmer areas where there tends to be a lack of nutrients, and greens and reds represent cooler nutrient-rich areas which support life. The nutrient-rich areas include coastal regions where cold water rises from the sea floor bringing nutrients along and areas at the mouths of rivers where the rivers have brought nutrients into the ocean from the land.
In praise of CO2
With less heat and less carbon dioxide, the planet could become less hospitable and less green
Financial Post, Don Mills, Ontario
Saturday, June 07, 2008
Planet Earth is on a roll! GPP is way up. NPP is way up. To the surprise of those who have been bearish on the planet, the data shows global production has been steadily climbing to record levels, ones not seen since these measurements began.
GPP is Gross Primary Production, a measure of the daily output of the global biosphere –the amount of new plant matter on land. NPP is Net Primary Production, an annual tally of the globe’s production. Biomass is booming. The planet is the greenest it’s been in decades, perhaps in centuries.
Until the 1980s, ecologists had no way to systematically track growth in plant matter in every corner of the Earth — the best they could do was analyze small plots of one-tenth of a hectare or less. The notion of continuously tracking global production to discover the true state of the globe’s biota was not even considered.
Then, in the 1980s, ecologists realized that satellites could track production, and enlisted NASA to collect the data. For the first time, ecologists did not need to rely on rough estimates or anecdotal evidence of the health of the ecology: They could objectively measure the land’s output and soon did — on a daily basis and down to the last kilometer.
The results surprised Steven Running of the University of Montana and Ramakrishna Nemani of NASA, scientists involved in analyzing the NASA satellite data. They found that over a period of almost two decades, the Earth as a whole became more bountiful by a whopping 6.2%. About 25% of the Earth’s vegetated landmass — almost 110 million square kilometres — enjoyed significant increases and only 7% showed significant declines. When the satellite data zooms in, it finds that each square metre of land, on average, now produces almost 500 grams of greenery per year.
Why the increase? Their 2004 study, and other more recent ones, point to the warming of the planet and the presence of CO2, a gas indispensable to plant life. CO2 is nature’s fertilizer, bathing the biota with its life-giving nutrients. Plants take the carbon from CO2 to bulk themselves up — carbon is the building block of life — and release the oxygen, which along with the plants, then sustain animal life. As summarized in a report last month, released along with a petition signed by 32,000 U. S. scientists who vouched for the benefits of CO2: “Higher CO2 enables plants to grow faster and larger and to live in drier climates. Plants provide food for animals, which are thereby also enhanced. The extent and diversity of plant and animal life have both increased substantially during the past half-century.”
From the 2004 abstract: Our results indicate that global changes in climate have eased several critical climatic constraints to plant growth, such that net primary production increased 6% (3.4 petagrams of carbon over 18 years) globally. The largest increase was in tropical ecosystems. Amazon rain forests accounted for 42% of the global increase in net primary production, owing mainly to decreased cloud cover and the resulting increase in solar radiation.
Lush as the planet may now be, it is as nothing compared to earlier times, when levels of CO2 and Earth temperatures were far higher. In the age of the dinosaur, for example, CO2 levels may have been five to 10 times higher than today, spurring a luxuriantly fertile planet whose plant life sated the immense animals of that era. Planet Earth is also much cooler today than during the hothouse era of the dinosaur, and cooler than it was 1,000 years ago during the Medieval Warming Period, when the Vikings colonized a verdant Greenland. Greenland lost its colonies and its farmland during the Little Ice Age that followed, and only recently started to become green again.
This blossoming Earth could now be in jeopardy, for reasons both natural and man-made. According to a growing number of scientists, the period of global warming that we have experienced over the past few centuries as Earth climbed out of the Little Ice Age is about to end. The oceans, which have been releasing their vast store of carbon dioxide as the planet has warmed — CO2 is released from oceans as they warm and dissolves in them when they cool — will start to take the carbon dioxide back. With less heat and less carbon dioxide, the planet could become less hospitable and less green, especially in areas such as Canada’s Boreal forests, which have been major beneficiaries of the increase in GPP and NPP.
Doubling the jeopardy for Earth is man. Unlike the many scientists who welcome CO2 for its benefits, many other scientists and most governments believe carbon dioxide to be a dangerous pollutant that must be removed from the atmosphere at all costs. Governments around the world are now enacting massive programs in an effort to remove as much as 80% of the carbon dioxide emissions from the atmosphere.
If these governments are right, they will have done us all a service. If they are wrong, the service could be all ill, with food production dropping world wide, and the countless ecological niches on which living creatures depend stressed. The second order effects could be dire, too. To bolster food production, humans will likely turn to energy intensive manufactured fertilizers, depleting our store of non-renewable resources. Techniques to remove carbon from the atmosphere also sound alarms. Carbon sequestration, a darling of many who would mitigate climate change, could become a top inducer of earthquakes, according to Christian Klose, a geohazards researcher at Columbia University’s Lamont-Doherty Earth Observatory. Because the carbon sequestration schemes tend to be located near cities, he notes, carbon-sequestration-caused earthquakes could exact an unusually high toll.
Amazingly, although the risks of action are arguably at least as real as the risks of inaction, Canada and other countries are rushing into Earth-altering carbon schemes with nary a doubt. Environmentalists, who ordinarily would demand a full-fledged environmental assessment before a highway or a power plant can be built, are silent on the need to question proponents or examine alternatives.
Earth is on a roll. Governments are too. We will know soon enough if we’re rolled off a cliff.