Climate Compass Blog
Scientists have typically been cautious when discussing the link between a single extreme weather event and climate change, preferring to focus on broader trends. Previous work, including a paper I wrote with Jay Gulledge four years ago, described a framework for how to think about the link.
But a new report from the National Academies of Sciences (NAS) is making the connection more clear by defining the relative contributions of climate change and other natural sources to the risk of individual weather events. The NAS report – an exhaustive, systematic examination of the peer-reviewed literature – finds high confidence in attribution studies linking individual extreme heat and cold events and climate change, and a more moderate confidence level for several other types of events.
Climate change is making extreme weather more likely. But individual weather events like heat waves or hurricanes are always the product of several risk factors, such as El Nino, climate change or other natural variability, akin to how a poor diet and smoking increase the risk of poor health later in life.
Extreme event attribution attempts to quantify the influence of climate change in comparison to other factors. Determining to what extent climate change strengthened or weakened the event can further our understanding of how much impact climate change is having on our weather.The NAS report assigns a confidence level to the climate impact for a variety of weather events based on three supporting lines of evidence:
- The physical mechanisms that link climate change to a particular extreme
- The length and quality of the observational record showing the baseline risk level and changes to date
- Computational climate modeling showing an increase in risk for a class of extreme event
The report finds the strongest links to climate change for extreme heat and cold, with the highest level of confidence across all three lines of evidence. Drought and extreme rainfall have medium confidence for physical understanding, observation and modeling. Extreme snowfall has medium conference for two out of three, physical understanding and modeling, while the observational record for snowfall is poor.
We’re seeing new movement toward phasing down the fastest-growing group of greenhouse gases – hydrofluorocarbons, or HFCs. These chemicals are widely used in refrigerators, air conditioners, foam products, and aerosols. And while they don’t stay in the atmosphere long, they can trap 1,000 times or more heat compared to carbon dioxide.
This week, the U.S. Environmental Protection Agency (EPA) proposed new regulations demonstrating its commitment to limiting the use of HFCs domestically. It proposed changes to its significant new alternatives program (SNAP) aimed at expanding the list of acceptable alternatives that minimize impacts on global warming while also restricting the use of HFCs in sectors where alternatives are now available. EPA estimates the proposed rule could avoid up to 11 million metric tons of carbon dioxide equivalent in 2030, which is equal to the energy-related emissions from about one million homes for one year.
Internationally, one sign of growing support for acting on HFCs came this month during the first visit by a U.S. president to Argentina in almost two decades. President Obama and newly elected Argentinian President Mauricio Macri explored opportunities to partner to address global challenges like climate change.
They affirmed their commitment to take action this year to amend the Montreal Protocol to phase down HFCs, which are substitutes for ozone-depleting chlorofluorocarbons (CFCs) that were successfully phased out under the 1989 Montreal Protocol. The two leaders also endorsed the understandings reached at the Dubai Montreal Protocol meeting in November 2015 on financial support for developing countries to implement an HFC phasedown.
A key opportunity will come next week when Montreal Protocol negotiators meet in Geneva to build on the progress made toward reaching agreement this year on an HFC phasedown amendment.
|Josh Wiener of MetLife, Kevin Rabinovich of Mars Inc., Rusty Hodapp of Dallas-Fort-Worth International Airport and Rob Bernard of Microsoft share the strategies that helped them win Climate Leadership Awards with David Rosenheim of The Climate Registry at the fifth annual Climate Laedership Conference, March 10 in Seattle.|
Climate action can start with an idea, but it takes a goal and a plan to get there to make that idea a reality.
When the folks at Microsoft began their current sustainability journey in 2007, “There was well-intentioned chaos,” according to Rob Bernard, the company’s chief environmental strategist. When the Clinton Foundation asked the software maker for a tool to monitor carbon in cities, “That made us think that, internally, we needed to have a strategy on sustainability,” Bernard said in his remarks at the fifth annual Climate Leadership Conference (CLC) in Seattle earlier this month.
That strategy led Microsoft to set and achieve its first public greenhouse gas goal, a 30 percent reduction within five years. Once that was met, the company then set -- and met -- an even more ambitious goal: carbon neutrality.
Microsoft was one of 13 organizations, three partnerships, and one individual honored with 2016 Climate Leadership Awards for accomplishments in reducing greenhouse gas emissions and driving climate action. The were given by the U.S. Environmental Protection Agency’s (EPA), in collaboration with C2ES and The Climate Registry.
The following was published in March 2016 on the EcoWomen blog. View the original post here.
I let out a cheer when Leonardo DiCaprio mentioned climate change during his Oscars acceptance speech. But concern about climate extends far beyond the red carpet.
Religious leaders, military officials, mayors, governors, business executives, and leaders of the world’s nations are all speaking about the need to address the greenhouse gas emissions that threaten our environment and economies.
Last December, world leaders reached a landmark climate agreement at the UN Climate Change Conference (COP 21) that commits all countries to contribute their best efforts and establishes a system to hold them accountable. COP 21’s Paris Agreement also sent a signal to the world to ramp up investment in a clean energy and clean transportation future.
The U.S. committed to reduce its greenhouse gas emissions 26-28 percent below 2005 level by 2025. The U.S. Environmental Protection Agency (EPA)’s Clean Power Plan was touted as a key policy tool to help reach that goal. However, with the recent surprise stay of the rule by U.S. Supreme Court, can the U.S. still meet its climate pledge? Simply put, yes.
|Source: International Energy Agency|
For the second year in a row, the global economy grew and global carbon dioxide emissions did not.
Preliminary data from the International Energy Agency (IEA) indicate that energy-related carbon dioxide (CO2) emissions (from burning fossil fuels for electricity, transportation, industry, space heating and so on) remained unchanged from the previous two years at around 32.1 billion metric tons. Meanwhile, economic growth increased by more than 3 percent for the second consecutive year.
A couple years of data doesn’t necessarily translate into a trend. And continued ambition in the decades ahead - like we saw with the landmark Paris Agreement in December 2015 - will be required before we can announce that we have truly turned the corner on reducing CO2 emissions.
But the IEA noted that 90 percent of new electric generation in 2015 came from renewables. Yes, 90 percent. And this apparent decoupling – after decades of energy-related CO2 emissions moving in lockstep with economic growth -- is a positive sign that low-carbon policies may finally be gaining traction in many parts of the world.
The change is due to policies and market forces affecting two factors – energy intensity and fuel mix – both in China and in the developed economies.