170
The Chinese are rapidly shifting away from coal in any case toward much cleaner
natural gas to improve the dismal air quality in their expanding cities. Natural gas
emits only about half the carbon dioxide as coal per Btu of energy, so as almost a
side effect to clearing the air this change will reduce China’s GHG emissions substantially. China has been importing LNG because the nation’s conventional natural
gas resources are limited, and much of this is “sour gas” that contains corrosive and
toxic hydrogen sulfide. The country does have potentially very large shale gas
resources, and these are actively being developed (Soeder and Borglum 2019).
Other climate contrarians argue that the Earth’s climate has changed naturally in
the geologic past, and that any changes seen today are just part of a natural cycle.
While climate does change naturally over geologic time, anthropogenic climate
change is an abrupt and intense disruption superimposed on this natural signal.
Climate on Earth has ranged from the tropical heat of the Carboniferous coal
swamps to the frozen “snowball” Earth of the Cryogenian Period. Trying to make a
case for “natural” climate change ignores the fact that human civilizations developed during a period of climate stability that began after the last glaciation and has
lasted for about 10,000 years. This stable climate allowed for predictable seasons,
established coastlines, the development of agriculture, and the construction of cities
and civil institutions. Natural climate change happens slowly on human scales, over
tens of thousands of years. The anthropogenic increase in GHG has taken place far
more quickly than most changes to Earth systems. It is the impact of this rapid
change on climate that is a cause of concern.
NASA has produced the graphic shown in Fig. 9.3 from the analysis of air
bubbles trapped in Antarctic ice cores. The line reflects 400,000 years of changes in
atmospheric carbon dioxide concentrations from different layers of snow incorporated into the Antarctic ice cap. For those who claim that the climate change we are
now facing is a natural event, these data clearly show that none of the natural variations in CO 2 levels over the past half million years have been anywhere near as
dramatic as those from 1950 onward. Since this image was published in 2013, carbon dioxide concentration has climbed by another 15 ppm. Every thinking person
on Earth should find the graphic alarming.
Since the appearance of oxygen-emitting photosynthetic plants and the
transformation of most of the carbon dioxide in the early atmosphere into carbonate
rocks and fossil hydrocarbons, the Earth has developed natural feedback mechanisms
to maintain more-or-less consistent levels of carbon dioxide in the atmosphere.
Increased CO 2 from a volcanic eruption, for example, will be mitigated in a few
thousand years by the increased weathering of basaltic rocks, which tie up the carbon as solid minerals, and by increased plant growth, which turn carbon into organic
material. The problem with anthropogenic carbon dioxide from fossil fuel combustion is that we have emitted too much too quickly for the Earth to cope.
The most extreme climate change event in the relatively recent geological past
was the Paleocene-Eocene Thermal Maximum or PETM, which occurred about
56 Ma (Jardine 2011). An abrupt increase in atmospheric GHG led to a global temperature rise of up to 8 °C. The origin of the GHG responsible for this event is
9 Fossil Fuels and Climate Change
The Chinese are rapidly shifting away from coal in any case toward much cleaner
natural gas to improve the dismal air quality in their expanding cities. Natural gas
emits only about half the carbon dioxide as coal per Btu of energy, so as almost a
side effect to clearing the air this change will reduce China’s GHG emissions substantially. China has been importing LNG because the nation’s conventional natural
gas resources are limited, and much of this is “sour gas” that contains corrosive and
toxic hydrogen sulfide. The country does have potentially very large shale gas
resources, and these are actively being developed (Soeder and Borglum 2019).
Other climate contrarians argue that the Earth’s climate has changed naturally in
the geologic past, and that any changes seen today are just part of a natural cycle.
While climate does change naturally over geologic time, anthropogenic climate
change is an abrupt and intense disruption superimposed on this natural signal.
Climate on Earth has ranged from the tropical heat of the Carboniferous coal
swamps to the frozen “snowball” Earth of the Cryogenian Period. Trying to make a
case for “natural” climate change ignores the fact that human civilizations developed during a period of climate stability that began after the last glaciation and has
lasted for about 10,000 years. This stable climate allowed for predictable seasons,
established coastlines, the development of agriculture, and the construction of cities
and civil institutions. Natural climate change happens slowly on human scales, over
tens of thousands of years. The anthropogenic increase in GHG has taken place far
more quickly than most changes to Earth systems. It is the impact of this rapid
change on climate that is a cause of concern.
NASA has produced the graphic shown in Fig. 9.3 from the analysis of air
bubbles trapped in Antarctic ice cores. The line reflects 400,000 years of changes in
atmospheric carbon dioxide concentrations from different layers of snow incorporated into the Antarctic ice cap. For those who claim that the climate change we are
now facing is a natural event, these data clearly show that none of the natural variations in CO 2 levels over the past half million years have been anywhere near as
dramatic as those from 1950 onward. Since this image was published in 2013, carbon dioxide concentration has climbed by another 15 ppm. Every thinking person
on Earth should find the graphic alarming.
Since the appearance of oxygen-emitting photosynthetic plants and the
transformation of most of the carbon dioxide in the early atmosphere into carbonate
rocks and fossil hydrocarbons, the Earth has developed natural feedback mechanisms
to maintain more-or-less consistent levels of carbon dioxide in the atmosphere.
Increased CO 2 from a volcanic eruption, for example, will be mitigated in a few
thousand years by the increased weathering of basaltic rocks, which tie up the carbon as solid minerals, and by increased plant growth, which turn carbon into organic
material. The problem with anthropogenic carbon dioxide from fossil fuel combustion is that we have emitted too much too quickly for the Earth to cope.
The most extreme climate change event in the relatively recent geological past
was the Paleocene-Eocene Thermal Maximum or PETM, which occurred about
56 Ma (Jardine 2011). An abrupt increase in atmospheric GHG led to a global temperature rise of up to 8 °C. The origin of the GHG responsible for this event is
9 Fossil Fuels and Climate Change