“Climate change is one of, if not the greatest challenge of our time.”
The science is as certain as anything in science can be, it’s as certain as the science of gravity. We have warmed the planet by about one degree Celsius, that’s about a degree and a half Fahrenheit, from the greenhouse gases that we’ve already put into the atmosphere for about 100 years, from fossil fuel burning and other human activities. And we are on track to hit 2 degrees Celsius warming by the middle of this century if we continue to burn fossil fuels as usual.
We are already beginning to feel the effects, 1 degree Celsius warming has fairly prominent implications. We saw three consecutive record years in 2014, 2015 and 2016, the hottest years on record.
Summer 2018, the extreme heatwaves, droughts, wildfires, floods that played out around the entire northern hemisphere throughout this summer, sent a message It was a message, from the climate that climate change has
arrived. The impacts of climate change are no longer subtle. In summer 2018 we saw them play out in real-time on our television screens, and our newspaper headlines, in our social media feeds. We’re seeing climate refugees, places like Kiribati low-lying island nations where coastal villages are receding.
Miami Beach regularly floods now, simply from a high tide because of the effects of global sea-level rise. We’ve lost roughly half of the sea ice in the Arctic. We are on course to see an ice-free Arctic in a matter of decades if we continue on the course that we’re on. Even if we drop carbon emissions to zero by tomorrow, we will continue to feel the effects of climate change for centuries to come.
The carbon emissions that we are putting into the atmosphere today have a long legacy in terms of the climate change that they are creating and will create.
Scientists from around the world come together to publish reports and say with definitive certainty: human-caused climate change is happening.
These reports inform climate policy and climate action at the national and international levels indicate that a heat increase of only 1 degree Celsius means at least 7% stronger winds and about 7% heavier rainfalls in any given storm. And thus considerably augmenting the risks and dangers for our habitats, food supply, and freshwater.
It’s critical to understand the science of climate change to understand the risks that we face and the necessary actions. So what’s the goal we’re working toward? Well as we’ve seen the science, particularly the science of climate change impacts tells us that once we warm the planet beyond about two degrees Celsius relative to pre-industrial time, we’re likely to see the most damaging and potentially irreversible changes in our weather and nature.
Two degrees Celsius is probably a line that we don’t want to cross. That means that policies ideally should be aimed at keeping warming below that dangerous two degrees Celsius level of warming. Now the Paris
agreement gets us about halfway there. It gets us halfway from business as usual warming of the planet which is taking us towards four, five degrees Celsius warming by the end of the century, it gets us halfway to stabilize warming below that two-degree mark which means that we have to make good on the Paris commitments, the countries of the world have to keep their commitments as agreed upon at the Paris summit. But we’ve got to go beyond Paris. We will need to ratchet up those commitments in the years ahead if we are to pursue a path that will keep warming below that dangerous two-degree level.
What is necessary to stabilize planetary warming below two degrees Celsius at this point? Well in 2014 through 2016, we saw carbon emissions plateau which is the first step in bending that curve downward which is essential if we’re going to keep CO2 levels below 450 parts per million and give ourselves a good chance of limiting warming below 2 degrees Celsius. Unfortunately, in 2017 and 2018 we saw carbon emissions tick up a little bit. What that means now, is that we’ve got to bring them down even more dramatically in the years ahead.
We now have to bend that curve downward, we have to see a decrease in carbon emissions in the year ahead of anywhere from 3 to 4 to 5 percent per year. And we are going to need policy incentives that help guide us on that pathway. Now I often encounter among people who are concerned about climate change an increasing amount of despair and pessimism. There’s a little bit too much of that, and there is this notion sometimes that this problem is too big that there’s no way we can tackle it. But the science is very empowering in that sense because the science tells us that there is still an opportunity.
The limitations at this point in keeping warming below catastrophic levels aren’t in the physics of the climate, the challenges are in the politics and the policies. And so at this point, we need to focus on doing what’s necessary from a policy standpoint to achieve the reductions that are still possible in keeping warming below dangerous levels. Yes, there’s great urgency to climate action today, but there are also reasons for hope that we can tackle this problem.