Human carbon dioxide emissions could prevent next Ice Age

Posted Jan 9, 2012 by JohnThomas Didymus
A team of scientists say that high levels of carbon dioxide in the atmosphere could prevent the next Ice Age. The scientists say that even if carbon emissions stopped today, enough has accumulated in the atmosphere to prevent the next Ice Age glaciation.
Factory emissions 
Thorold  Ontario  Canada
Factory emissions, Thorold, Ontario, Canada
The Telegraph reports that according to the team of scientist, in a study published in Nature Geoscience, high levels of carbon dioxide in the atmosphere that has been source of concern among environmental scientists could prevent glaciation. The scientists said that at the next Ice Age, the climate will cool down, but not as severely it could have with normal carbon dioxide levels. According to scientists, the Earth will probably not experience glaciation.
The team included scientists from University College London, the University of Florida and Norway's Bergen University. BBC reported that paleoclimatologist Luke Skinner, from Cambridge University, said: "At current levels of CO2, even if emissions stopped now we'd probably have a long interglacial duration determined by whatever long-term processes could kick in and bring [atmospheric] CO2 down."
The current level of carbon dioxide in the atmosphere is 390 parts per million. The scientists say that carbon dioxide levels in the atmosphere will need to drop down to 240 parts per million for glaciation to take place.
Some groups, according to BBC, are citing the study as evidence that human carbon dioxide emission may be beneficial for humankind. The UK lobby group Global Warning Policy Foundation, refers to an essay by Sir Fred Hoyle and Chandra Wickramasinghe, that said: "The renewal of ice-age conditions would render a large fraction of the world's major food-growing areas inoperable, and so would inevitably lead to the extinction of most of the present human population. We must look to a sustained greenhouse effect to maintain the present advantageous world climate. This implies the ability to inject effective greenhouse gases into the atmosphere, the opposite of what environmentalists are erroneously advocating."
Skinner says that his team had anticipated that some would use the study to justify their support of sustained greenhouse gas emissions. Skinner said: "It's an interesting philosophical discussion. Would we better off in a warm [interglacial-type] world rather than a glaciation? Probably we would. But it's missing the point, because where we're going is not maintaining our currently warm climate but heating it much further, and adding CO2 to a warm climate is very different from adding it to a cold climate.The rate of change with CO2 is basically unprecedented, and there are huge consequences if we can't cope with that."
Glacial and Interglacial periods
Scientists believe that the Earth goes through periods of glaciation with warmer interglacial periods in-between. During the last Ice Age, large areas of Europe, Asia and North America were covered in ice.
The cause of the cycles of Ice Age glaciation and interglacial period are the variations in the Earth's orbit known as the Milankovitch cycles. The variations involve the eccentricity of the Earth's orbit around the Sun, the degree to which its axis is inclined and the slow rotation of the Earth's axis. The precise time when the next glacial era will set in is debated because the various factors involved are not precisely understood by scientists. But based on their analysis of orbital data and studies of rock core samples drilled in the ocean floor, Skinner's team identified an episode called Marine Isotope Stage 19c (or MIS19c), about 780,000 years ago, as most closely resembling our present state. The scientists calculated from their study data that the new Ice Age ought to begin within 1,500 years. But with high levels of carbon dioxide emission from human activity, the scientists believe that a new Ice Age may not begin.
BBC reports that Lawrence Mysak, emeritus professor of atmosphere and oceanic studies at McGill University in Montreal, said: "The key thing is they're looking about 800,000 years back, and that's twice the 400,000-year cycle, so they're looking at the right period in terms of what could happen in the absence of anthropogenic forces....the problem is how do we get down to 240, 250, or whatever it is? Absorption by the oceans takes thousands or tens of thousands of years - so I don't think it's realistic to think that we'll see the next glaciation on the [natural] timescale."