Scientists from Scripps Institution of Oceanography (SIO) held a press conference on Friday, Feb. 2, to discuss a report issued by the Intergovernmental Panel on Climate Change (IPCC). This much-anticipated report was released by the IPCC in Paris and represents a summary of the “Physical Science Basis of Climate Change,” the full report that will be released in May. The report, which was referred to as “dire” and “sobering,” lists the evidence of humanity’s impact on the climate and predicts how the climate and environment is likely to change as a result.
SIO director Tony Haymet opened the conference by asserting that the IPCC report represents the most authoritative document of our current understanding of climate. Thousands of scientists from more than 130 countries contributed to the study, meaning it represents a consensus of the knowledge of the world’s scientists.
“The planet is warming ” land, atmosphere, oceans,” Haymet said, regarding the substance of the report. “This fact is unequivocal … almost certainly, this warming is caused by human activities.”
Haymet further explained the report states there is a 90- to 100-percent probability that the observed climate warming is caused by human activities.
SIO scientists played a prominent role in the crafting of the IPCC report. Distinguished professor Richard Somerville was in Paris, working on the finishing touches of the report, along with University of California, San Diego (UCSD) professor Mario Molina.
SIO has been at the forefront of climate change research for more than 50 years, as pointed out by SIO professor Ralph Keeling.
“In fact, it was a hard fact coming from Scripps, many years ago, that brought this whole topic of global warming to the world’s attention,” Keeling said. He was referring to the work of his father, the late Charles D. Keeling, who first demonstrated that carbon dioxide levels in the atmosphere were rising. He and SIO founder Roger Revelle rang the alarm bell about global warming.
Several other SIO researchers made major contributions to the current report. V. Ramanathan, director of the Scripps Center for Clouds, Chemistry and Climate, was a review editor of one chapter, charged with coordinating and organizing a team of authors. He spoke of the report’s major findings concerning the earth’s atmosphere, first describing how greenhouse gases, such as carbon dioxide, wrap around the planet like a blanket, trapping in heat that would otherwise dissipate into space. The higher the concentration of carbon dioxide, the more heat is trapped. The report defined a new term, “radiative forcing,” to estimate how much extra heat is being trapped by the atmosphere.
“The amount of heat we have trapped is equal to burning 25 trillion 60-watt light bulbs throughout the planet, all the time, every year, and we’ve been doing this for decades,” Ramanathan said.
This extra heat stays with the planet and is absorbed by the ocean and the air, raising temperatures.
Ramanathan went on to explain that air pollution, which adds fine particulate matter to the air, actually masks some of the effects of global warming. The tiny particles in the air reflect sunlight, preventing some of the sun’s heat from reaching the planet. This effect would be beneficial were it not for the wide variety of other health problems caused by air pollution.
“So when we get rid of the pollutants, which we have to, the global warming will accelerate,” Ramanathan said.
Global warming will have serious effects on the planet, as outlined by the report. Lynne Talley, an SIO oceanography professor, described how global warming will increase the rate of hydrological cycle ” the movement of water between clouds, rain, snow, rivers and oceans.
As a result, said Talley, “The drier areas will probably get drier, the wetter areas will get wetter. That means that we will have more desert here [in San Diego].”
The report also predicted that the additional heat will increase the frequency and severity of extreme weather events, such as droughts, rainstorms and hurricanes.
SIO marine geophysicist Tim Barnett described the report’s prediction that winter snow will melt faster each year. Mountain snow and glaciers normally act as a source of fresh water, providing a continuous flow as they slowly melt during the summer. As global warming melts all the snow and ice, this vital source of water will disappear.
“Basically, what we’re headed for on a global basis is a catastrophe with regard to water supply,” Barnett said.
Melting arctic ice and glaciers will also increase sea levels, perhaps by as much as 2 feet by the year 2100, if the worst-case scenario is played out, according to the report.
Dan Cayan, an SIO research meteorologist, explained how San Diego will feel the effects of global warming. In California, temperatures will rise 3 to 7 degrees Fahrenheit by 2100, spring will come earlier and snow will decrease and melt sooner, Cayan predicted.
“The alarming thing is this is just a taste of what is probably going to happen,” he said, adding that as the region gets warmer and drier and snow runoff declines, water management will become a major concern in California.
In light of these alarming predictions, Haymet said he hopes this report will serve as a call to action for the world community.
“The most prudent thing we can do now is to reduce carbon dioxide emissions now, and increasingly reduce them in the future,” said Haymet, who then stressed that the IPCC concerns science only.
While governments on the local, state and national level are responsible for setting policy to address the crisis of global warming, Haymet said he hopes that scientists will be included in future policy-making.
” To read more about how science impacts our lives, visit Matthew Busse’s blog, www.science-translator.com.