Qu: Why are humans to blame for climate change?
Every now and then I allow myself the luxury of believing one of those guilt-relieving theories that humans are not responsible for the rate at which the Earth’s climate is changing. There is no correlation between the increase in our GHG (green house gas) emissions and the 1.5-2C increase in temperature since the pre-industrial era.
No, nothing to do with me; climate change is just part of the natural pattern of the current interglacial period – or it’s due to the Earth’s 40,000-year tilt, or its 23,000-year wobble – or can’t we blame Sunspot activity?
Then I take a look around and face facts. Over the last 250 years, by digging up and burning coal, oil and natural gas, humans have put carbon, safely captured in the Earth’s sinks, back into the atmosphere.
Now, as The Stern report showed in 2006, the concentration of carbon dioxide in the atmosphere exceeds the highest levels in the period for which data exists (covering the past 650,000 years). The increase of carbon dioxide causes global temperatures to rise, higher temperatures reduce the ability of the earth and oceans to absorb carbon dioxide, leaving more in the air. This creates a dangerous feedback: higher temperatures increase carbon dioxide concentrations and higher concentrations increase temperatures.
According to the Stern report greenhouse gas concentrations in the atmosphere at the time were 430ppmCO 2e (parts per million of carbon dioxide equivalent, which includes methane) and rising at 2ppm each year. Above 450ppm CO2 global temperatures would have a 50% chance of rising to 2°C above pre-industrial levels and a 5% chance of reaching 3.5°C.
This is no time to kid ourselves; we are firmly in the Anthropocene age: a new era in planetary history in which humans impact on the ecosphere. Yet some people are still in denial. Scientists are reported as being “astonished” by incidents such as the collapse of the Larson B ice shelf in the Antarctic or methane bubbling from permafrost. In reality, the scientific community has seen climate change coming for over 180 years (see the work of Joseph Fourier on gases in 1827). Source
In 1985 an international group of scientists got together with climate modelers (meeting as individuals so their report was unconstrained by commercial or political pressure), they predicted, “substantial warming” that was unambiguously “attributable to human activities”. No ifs, no buts, no maybes. This meeting led to the Rio Earth Summit in 1992, then to Kyoto in 1997.
At the December 2007 UN Climate Change Conference in Bali the last few countries finally agreed that human activity is responsible for global warming. This conclusion has been reached despite the best efforts of Big Oil, which has given massive grants to any scientist or pseudo-scientist who would cast a few doubts. It had taken politicians 22 years to catch up with scientists.
The question now is; if humans have caused global warming is it too late to do something about it? Carbon dioxide takes time to permeate the atmosphere and cause global warming, so present temperatures are the result of 30-year- old emissions. Today’s emissions will therefore impact on temperatures during the coming 30 years.
Thankfully politicians are beginning to take climate change seriously, the recent increase in carbon reduction goals from 60% to 80% by 2050 shows that the UK government at least, is finally realizing the urgency. Another leap forward is an amendment to the Energy Bill meaning that individuals who contribute renewable energy to the grid will be financially rewarded. This energy scheme has been successful in Germany and is a step towards empowering individuals to create a future that is not dependant on oil.
All these steps forward have been triggered by groups of individuals who have refused to bury their heads and have instead campaigned for change. We can make a difference and now is the time to do it.
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