Ridley: Rejoice, the Earth Is Becoming Greener
By Matt Ridley
Bottom line: In 2016 a paper was published by 32 authors from 24
institutions in eight countries that analysed satellite data and concluded
that there had been a roughly 14% increase in green vegetation over 30
years. The study attributed 70% of this increase to the extra carbon dioxide
in the atmosphere. The lead author on the study, Zaichun Zhu of Beijing
University, says this is equivalent to adding a new continent of green
vegetation twice the size of the mainland United States.
Global greening has affected all ecosystems - from arctic tundra to coral
reefs to plankton to tropical rain forests - but shows up most strongly in
arid places like the Sahel region of Africa, where desertification has
largely now reversed. This is because plants lose less water in the process
of absorbing carbon dioxide if the concentration of carbon dioxide is
higher. Ecosystems and farms will be less water-stressed at the end of this
century than they are today during periods of low rainfall.
There should have been no surprise about this news. Thousands of experiments
have been conducted over many years in which levels of CO2 had been
increased over crops or wild ecosystems and boosted their growth. The owners
of commercial greenhouses usually pump CO2 into the air to speed up the
growth of plants. CO2 is plant food.
This greening is good news. It means more food for insects and deer, for
elephants and mice, for fish and whales. It means higher yields for farmers;
indeed, the effect has probably added about $3 trillion to farm incomes over
the last 30 years. So less land is needed to feed the human population and
more can be spared for wildlife instead.
Yet this never gets mentioned. In their desperation to keep the
fearmongering on track the activists who make a living off the climate
change scare do their best to ignore this inconvenient truth. When they
cannot avoid the subject, they say that greening is a temporary phenomenon
that will reverse in the latter part of this century. The evidence for this
claim comes from a few models fed with extreme assumptions, so it cannot be
trusted.
******************************
@mattwridley <https://www.twitter.com/@matt
Amid all the talk of an imminent planetary catastrophe caused by emissions
of carbon dioxide, another fact is often ignored: global greening is
happening faster than climate change. The amount of vegetation growing on
the earth has been increasing every year for at least 30 years. The evidence
comes from the growth rate of plants and from satellite data.
In 2016 a paper was published by 32 authors from 24 institutions in eight
countries that analysed satellite data and concluded that there had been a
roughly 14% increase in green vegetation over 30 years. The study attributed
70% of this increase to the extra carbon dioxide in the atmosphere. The lead
author on the study, Zaichun Zhu of Beijing University, says this is
equivalent to adding a new continent of green vegetation twice the size of
the mainland United States.
Global greening has affected all ecosystems - from arctic tundra to coral
reefs to plankton to tropical rain forests - but shows up most strongly in
arid places like the Sahel region of Africa, where desertification has
largely now reversed. This is because plants lose less water in the process
of absorbing carbon dioxide if the concentration of carbon dioxide ishigher. Ecosystems and farms will be less water-stressed at the end of this
century than they are today during periods of low rainfall.
There should have been no surprise about this news. Thousands of experiments
have been conducted over many years in which levels of CO2 had been
increased over crops or wild ecosystems and boosted their growth. The owners
of commercial greenhouses usually pump CO2 into the air to speed up the
growth of plants. CO2 is plant food.
This greening is good news. It means more food for insects and deer, for
elephants and mice, for fish and whales. It means higher yields for farmers;
indeed, the effect has probably added about $3 trillion to farm incomes over
the last 30 years. So less land is needed to feed the human population and
more can be spared for wildlife instead.
Yet this never gets mentioned. In their desperation to keep the
fearmongering on track the activists who make a living off the climate
change scare do their best to ignore this inconvenient truth. When they
cannot avoid the subject, they say that greening is a temporary phenomenon
that will reverse in the latter part of this century. The evidence for this
claim comes from a few models fed with extreme assumptions, so it cannot be
trusted.
This biological phenomenon can also help to explain the coming and going of
ice ages. It has always been a puzzle that ice ages grow gradually colder
for tens of thousands of years, then suddenly warmer again in the space of a
few thousand years, at which point the huge ice caps of Eurasia and North
America collapse and the world enters a warmer interlude, such as the one we
have been enjoying for 10,000 years.
Attempts to explain this cyclical pattern have mostly failed so far. Carbon
dioxide levels track the change, but these rise after the world starts to
warm and fall after the world starts to cool, so they are not the cause.
Changes in the shape of the earth's orbit play a role, with ice sheets
collapsing when the northern summers are especially warm, but only some of
these so-called "great summers" result in deglaciation.
Recent ice cores from the Antarctic appear to have fingered the culprit at
last: it's all about plants. During ice ages, the level of carbon dioxide in
the atmosphere steadily drops, because colder oceans absorb more of the gas.
Eventually it reaches such a low level - about 0.018% at the peak of the
last ice age - that plants struggle to grow at all, especially in dry areas
or at high altitudes. As a result gigantic dust storms blanket the entire
planet, reaching even Antarctica, where the amount of dust in the ice spikes
dramatically upward. These dust storms blacken the northern ice sheets in
particular, making them highly vulnerable to rapid melting when the next
great summer arrives. The ice age was a horrible time to be alive even in
the tropics: cold, dry, dusty and far less plant life than today.
As Svante Arrhenius, the Swede who first measured the greenhouse effect,
said: "By the influence of the increasing percentage of carbonic acid in the
atmosphere, we may hope to enjoy ages with more equable and better
climates." Enjoy the lush greenery of the current world and enjoy the fact
that green vegetation is changing faster than global average temperatures.
This first appeared
<https://www.weltwoche.ch/ausg
uns-die-weltwoche-ausgabe-27-2
Matt Ridley is a scientist, journalist, and businessman. He is a board
member of HumanProgress.org.
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