Climate Change Series: Mitigating The Damage

Introduction

Mitigating climate change doesn't sound as monumental as ending, or reversing climate change. But with global phenomenon already "contributing to the deaths of nearly 400,000 people a year and costing the world more than $1.2 trillion... annually," according to the Climate Vulnerability Monitor, MIT professor Henry "Jake" Jacoby explains why efforts to mitigate climate change may be crucial to determining the next generation's quality of life.

Henry ("Jake") Jacoby is William F. Pounds professor emeritus in the MIT Sloan School of Management, and former co-director of the MIT Joint Program on the Science and Policy of Global Change.

Talking about mitigating climate change risk is a bit like the story of the man arrested for murder whose lawyer said to him, "I've got good news and bad news. The bad news is the blood found at the crime scene matches your DNA. The good news is your cholesterol level is down to 160."

First, the bad news about climate change: The quantity of greenhouse gases humans have pumped into the atmosphere since the dawn of the industrial age is already changing the earth's climate and raising global temperatures. What’s not widely recognized is that simply stabilizing global greenhouse gas emissions at today's levels will not stabilize their atmospheric concentrations and effects on climate. Much deeper cuts will be required. Moreover, even if we succeed in reducing future emissions drastically, our children and grandchildren will have to live with the consequences of global warming --not just higher temperatures, but more severe storms, sea level rise, fire, drought and other environmental changes.

With no additional mitigation policy, we estimate there's about a 50/50 chance that global temperatures will rise by as much as 5 degrees Celsius by the end of this century. There's almost a one in four chance global temperatures will rise by 6 C or more.

Over the past two decades, diplomats have tried to negotiate a deal to limit atmospheric concentrations of "Kyoto gases" (carbon dioxide, methane, nitrous oxide and other industrial gases). Their ultimate goal: to curb global temperature increases to 2 C by the year 2100. However, after analyzing the data, the objective looks daunting.

Whatever we and the other nations do, climate change will adversely affect future generations. By steadily pressing ahead to create a non-carbon-based economy by whatever means available, we can limit the damage.

For example, one specific target is to limit atmospheric concentrations to about 450 parts per million (ppm). But given that the concentration of these gases has already risen from 275 ppm in the late 18th century to around 440 ppm today, and is climbing steadily, it's doubtful we can achieve that goal.

But all is not lost. According to our calculations at MIT's Joint Program on the Science and Policy of Global Change, even if we limit atmospheric concentrations of the Kyoto gases to a more modest 650 ppm, the high-end risks of climate change — temperature increases of 5 to 7 C — disappear. In other words, our grandchildren would still have to live with the disruptive effects of climate change, but they wouldn’t have to face the most catastrophic scenarios.

That's the good news about climate change: almost anything we do to limit greenhouse gas emissions has its biggest effect on the worst possible outcomes. That's why it's worth keeping up the fight to reduce greenhouse gas emissions even though some targets will be hard to meet.

Here in the U.S., despite the national gridlock on climate change policy, energy-related carbon dioxide emissions have dropped in recent years — in part because of the recession but also due to a shift from coal to natural gas as a power source. The fact that President Obama talked about climate change in his inaugural address, plus the effect of recent storms and drought on public understanding of the risk, may help shift the debate toward a more aggressive policy response.

Right now, the U.S. has a cobbled together quilt of state, regional and national policies — automobile mileage standards, appliance efficiency ratings, renewable energy subsidies — that indirectly limit greenhouse gas emissions. From an economic perspective, the cheapest and best way to reduce emissions would be with a carbon tax, or a cap-and-trade system that places a price on carbon emissions. It's a win/win/win solution. It would 1.) lower greenhouse gases emissions and oil imports, 2.) increase revenue which could be used to cut other taxes, and 3.) have a neutral-to-positive effect on economic growth. If a price penalty for emitting greenhouse gases is not politically feasible, then more expensive regulatory measures are going to be the way forward.

Whatever we and the other nations do, climate change will adversely affect future generations. By steadily pressing ahead to create a non-carbon-based economy by whatever means available, we can limit the damage.

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