PNNL helps advance science behind climate change

Climate change is a global issue. And in the past few weeks, it received global attention as leaders from more than 190 countries met in Paris to discuss how to address climate change by reducing greenhouse gas emissions into the atmosphere. The United Nations Framework Conference on Climate Change — known as COP21 — recently ended with pledges to reduce emissions and accelerate deployment of clean energy alternatives.

As a leader in climate science, the Department of Energy’s Pacific Northwest National Laboratory is conducting research that is directly relevant to — and helped inform — the discussions that took place in Paris. For example, one goal of COP21 was to reach an international agreement that will keep the average global temperature from rising more than 2 degrees Celsius. This threshold is based on studies by the Intergovernmental Panel on Climate Change that indicate that global warming of more than 2 degrees will have serious consequences. For years, PNNL researchers have contributed to this respected international panel and its assessments of global climate, the impacts of climate change and options to curtail and adapt to it.

In the weeks before COP21, individual countries announced contributions they are willing to make to combat global climate change. PNNL scientists were among those leading a study published in the prestigious journal, Science, that shows if countries meet their pledges and ramp up efforts as the century goes on, we improve our chances of limiting global warming to 2 degrees C. The team also showed that if countries did nothing to reduce emissions, the temperature increase could easily exceed 4 degrees C. They integrated models of the Earth’s energy, economic and agricultural systems into climate models to estimate the probabilities of temperature changes for different future scenarios.

Understanding and predicting climate change and its impact is a huge scientific challenge because of the underlying complex chemical processes and variables in the Earth system. PNNL’s robust climate research program centers on three key areas: conducting integrated assessments like those just discussed, advancing fundamental atmospheric science and studying the regional impacts of climate change.

In one example of our fundamental climate science research, PNNL staff and their collaborators took a close look at the chemical components and interactions within the brown haze that often lingers over major cities on sunny days. Their study led to new insights into a type of particle called “brown carbon” that is composed of organic molecules that absorb and retain heat. Understanding how these particles change and behave could lead to better predictive models for climate change and be used to inform decisions about energy production and use.

In other research, scientists studying the Southern Ocean surrounding Antarctica discovered that ocean life is responsible for up to half the cloud droplets that appear and disappear throughout the summer. Tiny airborne droplets and solid particles called aerosols are given off by marine organisms, increasing cloud droplets and boosting the amount of sunlight reflected back to space.

Additionally, PNNL provides leadership for DOE’s Atmospheric Radiation Measurement (ARM) Climate Research Facility, with support from eight other national laboratories. ARM allows researchers around the world to conduct climate and atmospheric research by providing access to cutting-edge instrumentation that gathers massive amounts of climate data. The instruments and equipment at three primary locations representing a range of climate conditions obtain long-term measurements that scientists use to characterize how atmospheric properties evolve and to evaluate models under different meteorological conditions.

PNNL researchers also are interested in the impact of climate change at regional scales, for example, how global warming might affect the snowpack in the Cascades. These studies shed light on potential impacts, such as increased rain versus snow, which in turn affects hydroelectricity, fish and wildlife, and irrigation for crops.

In another regional example, scientists combined risk analysis and climate modeling to assess the risk of fire in California. Using worst-case-scenario assumptions of greenhouse gas emissions, scientists concluded that the number of days of extreme fire risk in California could be six times greater by the end of the century than it is today. The combination of increased carbon dioxide in the air and a warmer, wetter climate by the end of the 21st century could result in more vegetation, or fuel, for fires. The research also showed that reducing emissions could reduce the risk.

Climate change and carbon dioxide emissions are hot topics for politicians, environmentalists, industrialists and scientists. At PNNL, we are conducting research that will enhance our understanding of the complex earth system, including our ability to predict climate change and its impact. Research like this is vital. It provides our leaders with the scientific basis for policy decisions that affect us all — and PNNL is proud to be at the forefront of this field.

This story was originally published December 13, 2015 at 9:44 PM with the headline "PNNL helps advance science behind climate change."