It’s fun and interesting to look back over the last decade and think about what has happened and how far we have come. Round years are arbitrary, but it’s a sufficient trigger to take stock and hopefully gain some perspective on the medium course of history. There is a lot to say about the 2010s, and I may take the opportunity to say more, but I want to discuss in this essay what is perhaps our greatest challenge and disappointment over the last decade. In many ways this has been a lost decade for climate change mitigation.

Over the last decade the scientific evidence (and resulting consensus) that the planet is warming, that humans are the primary driver of this trend, and that the consequences are not likely to be good, has only become greater. The last five years have been the hottest five years on record, and this has been the case for most of the last decade. The year 2016 was the hottest, because it was an El Niño year (short term fluctuations will still be overlaid on top of the longer term trend) but the trend is unmistakable. The story of the world’s ice is more complex, with greater regional and year-to-year variations, but total global ice has been decreasing, and if anything accelerated over the last decade. The Greenland ice sheet in particular experienced accelerated melting. As a result there is a real and growing scientific consensus, north of 97% among relevant scientists, that anthropogenic climate change is happening.

We are also experiencing more extreme weather events. We are seeing more droughts, fires, heat waves, and more powerful storms. In the last decade it become clear that, while the worst consequences of climate change are decades and even centuries in the future, we are starting to see real consequences now.

Economists have started to weigh in as well. Numerous studies were published over the last decade, concluding that – climate change will cost the world many billions of dollars and will reduce economic growth, costing even more. Further, the option of allowing climate change to happen and adapting to the results will likely be the costliest option. In addition to the monetary cost, there is a quality of life cost. Extreme weather causes displacement, psychological trauma, and social upheaval. If you think we are having a refugee crisis now, just wait as flooding increasing and more locations become essentially uninhabitable.

Partly because this was the decade that climate change became real for many people, public opinion has shifted. There is now a majority public opinion in the US that climate change is happening, is human-caused, and we should do something about it. A solid 67% say global warming is happening, but only 53% say it is mostly caused by people (with 14% unsure). So we still have some work to do to align public opinion with scientific opinion, but the numbers are moving in the correct direction. But, despite uncertainty, a strong majority of the public (62-83% across various policies) support research and policies that could mitigate climate change. So even when people toe the political line, it seems that they still support policies to prevent global warming, which implies that down deep they fear it may be real.

Some researchers have focused on a practical issue – how much would people be willing to personally pay to mitigate climate change? Answers to this question vary widely, based on who is asking the question and how. One survey found that only 28% of people would be willing to pay $10 a month to combat climate change, but 30% would be willing to pay $20 per month, and 16% would be willing to pay $100 per month. This is definitely a glass half empty-half full situation – there is some willingness to pay, but not a majority (except at the insignificant $1 per month level, 57%). A Yale study took a different approach, and tried to estimate the average amount of money the American public would be willing to pay per year for climate change, and came up with $177 per year (with a confidence interval of $101-$587). That’s $22.3 billion per year, which could be used for research, or to subsidize clean energy.

So essentially the last decade saw a strengthening of the evidence for climate change, and much better understanding of the implications and costs, and a significant increase in public support of the science and policy to do something about it. What it did not see, however, was any real policy or change in our energy infrastructure. We did get the Paris Climate Accord in 2015, with 200 nations agreeing to make a sincere effort to reduce their carbon footprint with the goal of limiting the increase in global temperatures to 2.0 degrees C above pre-industrial levels by the end of the century. Even at that level, there will be some huge negative consequences, but that goal was thought to be realistic. But, the agreement has no teeth, and most countries are not meeting their goals. And of course, Trump famously pulled out of the agreement.

By a first approximation, the world did basically nothing to combat change in the last decade. Some technologies have improved, including wind, solar, and electric vehicles. Whatever gains were made were simply due to technological advancement, not any dedication to mitigating climate change. And – those gains were more than offset by the world’s growing energy needs. Global carbon emissions continued to increase over the last decade, hitting a new high in 2019. We haven’t even started to decrease the rate at which we are releasing CO2 into the atmosphere.

It is now increasingly clear that the time to take major action to reduce climate change was 10 years ago – but we lost the last decade through political inaction. There is a real reason to be concerned that the world is basically too politically dysfunctional to tackle the challenge of climate change. I think we are scientifically up to the task, but that is irrelevant if we cannot must the political will.  It’s not as if we don’t know what we need to do. We can debate the best ways to accomplish our goals, but the goals themselves are pretty clear.

First, we need to maximize renewable energy sources as quickly as possible. Wind and solar are currently cheaper than other forms of adding new energy to the grid, and they will likely get cheaper still. However, getting to significant renewable penetration will require updating energy grids. Also, we need to displace coal and then other forms of fossil fuel as quickly as possible as the main source of on-demand baseload energy. There are many ways to do this, and we need to pursue them all. This includes hydroelectric, geothermal, and grid storage. But this also must include nuclear energy. We need to extend the use of existing nuclear power plants and rapidly develop the next generation (Gen 4) plant designs. Unfortunately, the party that most supports action against climate change is lingering in their outdated anti-nuclear position and could actually be a net-negative to climate mitigation over the next few decades by opposing nuclear.

I want to emphasize that it is never too late to take action to keep climate change from getting even worse. It is now clear that it is too late to prevent significant climate change – 1.5C is probably already a done deal (we are currently at 1.1C), and perhaps even 2.0C is practically unavoidable. There is also the issue of climate tipping points, a topic that has also become increasingly clear over the last decade. Positive feedback loops means that warming will cause more warming. The question really is, at what temperature will be arrive at a new equilibrium point. That is hard to model, but the worst-case (and not improbable) scenarios are bad. We may already be committed to 3C or higher, and 10 meters or more of ocean level increase, over the next thousand years or so. The next decade may be our last chance to avoid a cascade of climate events that commit the world to a new equilibrium point that will radically change the Earth’s climate. But even then, the more we do, the slower these changes will occur, which will give us more time to adapt.

Looking back I think it’s clear that we lost the last decade, and that we cannot afford to lose another. The real question is – can public opinion break through the political dysfunction and galvanize the world toward meaningful action? The 2020 election may be the first real test of that question.