Here’s a challenge for readers: how many long-debunked-but-will-never-die climate denial themes can you spot in the following advertisement from the New York Times back in 2000 (you can read more about it here)
Knowing that weather forecasts are reliable for a few days at best, we should recognize the enormous challenge facing scientists seeking to predict climate change and its impact over the next century. In spite of everyone’s desire for clear answers it is not surprising that fundamental gaps in knowledge leave scientists unable to make reliable predictions about future changes.
A recent report from the National Research Council (NRC) raises important issues, including these still-unanswered questions (1) Has human activity already begun to change temperature and the climate, and (2) How significant will future change be?
The NRC report confirms that Earth’s surface temperature has risen by about 1 degree Fahrenhelt over the past 150 years. Some use this result to claim that humans are causing global warming, and they point to storms or floods to say that dangerous impacts are already under way. Yet scientists remain unable to confirm either contention.
Geological evidence indicates that climate and greenhouse gas levels experience significant natural variability for reasons having nothing to do with human activity. Historical records and current scientific evidence show that Europe and North America experienced a medieval warm period one thousand years ago, followed centuries later by a little ice age. The geological record shows even larger changes throughout Earth’s history. Against this backdrop of large poorly understood natural variability, it is impossible for scientists to attribute the recent small surface temperature increase to human causes.
Moreover, computer models relied upon by climate scientists predict that lower atmospheric temperatures will rise as fast as or faster than temperatures at the surface. However, only within the last 20 years have reliable global measurements of temperatures in the lower atmosphere been available through the use of satellite technology. These measurements show little if any warming.
Even less is known about the potential or negative impacts of climate change. In fact, many academic studies and yield experiments have demonstrated that increased levels of carbon dioxide can promote crop and forest growth.
So, while some argue that the science debate is settled and governments should focus only on near-term policies — that is empty rhetoric. Inevitably, future scientific research will help us understand how human actions and natural climate change may affect the world and help determine what actions may be desirable to address the long-term.
Science has given us enough information to know that climate changes may pose long-term risks. Natural variability and human activity may lead to climate change that could be significant perhaps both positive and negative. Consequently, people, companies and governments should take responsible actions now to address the issue.
One essential step is to encourage development of lower-emission technologies to meet our future needs for energy. We’ll next look at the promise of technology and what is being done today.