On March 31, the U.S. officially pledged to reduce greenhouse gas emissions as much as 28 percent below 2005 levels by the year 2025, joining the European Union, Mexico, Norway and Switzerland in submitting pledges for the upcoming United Nations climate talks. These efforts will culminate in December, when delegates from countries worldwide will gather in Paris to assess progress and action toward addressing climate change. The goal of this year’s meeting is substantial: for all nations to achieve a legally binding agreement for the world to stay below a 2 degree Celsius temperature rise above pre-Industrial time. 

The fundamental information needed for these negotiations, also known as the 21st Conference of the Parties, or COP21, is concrete data about global greenhouse gas emissions fueling climate change. That is where Rob Jackson, the Michelle and Kevin Douglas Provostial Professor, and his colleagues at the Global Carbon Project come in. Every year, scientists at the nongovernmental research organization conduct an inventory that provides the latest, most accurate data on global emissions and sinks of carbon dioxide, one of the most important greenhouse gases leading to climate change.

The Stanford Woods Institute for the Environment interviewed Jackson, a professor in Stanford’s School of Earth, Energy & Environmental Sciences and a senior fellow with the Woods Institute and the Precourt Institute for Energy, about his work as a chair of the Global Carbon Project’s Scientific Steering Committee. He was joined by Pep Canadell, a Global Carbon Project executive director and a research scientist at CSIRO, Australia's national science agency, to discuss their latest data and how they can be used for climate negotiations.

Can you define the “natural” carbon cycle and explain how excess CO2 in the atmosphere is created and contributes to climate change? 

JACKSON: The natural carbon cycle is the exchange of carbon between life and the earth’s physical environment, including the land and oceans. Burning fossil fuels takes carbon that has been locked deep underground and adds it to the atmosphere, warming the earth as a result. 

How does the Global Carbon Project measure and calculate emissions data? Does the project track other greenhouse gas emissions in addition to carbon?

CANADELL: Our carbon budget serves as a report card of the state of the carbon cycle. We take a look at the fundamental science of the carbon cycle, and then ask, “How are human activities changing the exchange of carbon between the land, atmosphere and oceans; and in turn, as we change the climate, how do these natural systems react?” We look at everything from the amount of emissions coming from each country, to emissions per capita, to the emissions that are coming from human activities like deforestation, fossil fuel use and cement production. Historical emissions are also an important factor because climate change is a cumulative problem. For example, China has been substantially emitting carbon emissions for the last 30 years, while the U.S. has been emitting them for over 120 years.

Why are these kind of data relevant for climate negotiations?

CANADELL: It is important for climate negotiations because we’re providing some of the most robust and up-to-date science, observations and modeling for leaders to consider when creating a new pact. This is particularly important for emissions and trends at the national level, which is of most importance to negotiations. 

Who is working with the Global Carbon Project and how do you all work together to account for global carbon emissions?

JACKSON: Hundreds of scientists from dozens of countries contribute their time, effort and ideas to the Global Carbon Project. We work together to organize the annual carbon dioxide budget, methane emissions data and many other efforts. We’re grateful for their help. And, by the way, everyone works for free.

How do Global Carbon Project researchers interact with negotiators?

CANADELL: The Global Carbon Project focuses on the fundamental science without getting involved with the complexities of the negotiations. By exposing the bare numbers – the bare facts – we make no arguments regarding who needs to do what. We provide this information for negotiators to make informed decisions. 

How does the Global Carbon Project report data?

CANADELL: Each year, the Global Carbon Project contributes to the Subsidiary Body for Scientific and Technological Advice, a body that directly advises the U.N. Convention on Climate Change, with advice on scientific, technological and methodological matters. We also engage in site meetings at annual Conferences of the Parties (COPs), such as the upcoming talks in December, where we present our latest data. Additionally, we are major contributors to the Intergovernmental Panel on Climate Change, the scientific body that produces reports with the most recent scientific, technical and socioeconomic information relevant to climate change. 

JACKSON: We want to make sure that our data are clearly articulated for anyone who wants to learn more. Our data live online at globalcarbonatlas.org, a tool that helps scientists, decision-makers and inquiring minds to understand emissions. 

What do you hope will emerge from COP21? Is there any current consensus on what the most likely outcomes will be?

JACKSON: What we all hope for is a roadmap for reducing greenhouse gas emissions globally. The roadmap needs to be both as fair and as inexpensive as possible. An agreement is long overdue.

You met as postdoctoral associates at Stanford two decades ago. What new opportunities do you hope to pursue together at the Global Carbon Project? 

CANADELL: Now, we’re working on a global assessment of all sources and sinks of methane, the second most important greenhouse gas leading to climate change. Emissions come from major industries, including livestock, rice paddies, gas and oil. Natural systems are also involved, for example, wetlands release methane. We’re exploring both the biological and human components of methane emissions, and how they are affecting global warming. 

JACKSON: We also have new studies on greenhouse gas emissions from the energy sector and how to help reduce them. In addition, we’re measuring urban emissions, particularly in the developing world, because more than half of the world’s population now live in cities. Finally, because water is so important around the world, the intersection of greenhouse gas emissions and water use is a critical priority. When we save energy, we save water; when we conserve water, we cut energy use and put money in the bank.