The medical journal The Lancet released a comprehensive review of the potential health effects of climate change today. In the paper, a blue-ribbon panel of experts from the fields of climate science, engineering, economics, medicine, and many others lay out powerful evidence of the public-health impacts climate change has already inflicted on us, as well as the dire consequences that await us in the near future. I have read many papers on climate change and health, and this one is both the most convincing and the most frightening. Here are three important take-home points.
Let’s start with the now-ness of the situation. Hollywood has conditioned us to believe that apocalypses are future events — alien invasions, robot rebellions, asteroid impacts, and the like. Since the very most serious effects of climate change won’t arrive for decades, we have an unfortunate tendency to assume it falls into this category. The fact that most reports discuss future deaths rather than past fatalities doesn’t help. For example, the World Health Organization estimated in 2014 that climate change would cause an additional 250,000 deaths annually between 2030 and 2050. Many of those people aren’t even born yet.
Why talk about tomorrow when you can talk about today? Climate change’s reign of terror has begun, says The Lancet’s expert panel, causing or worsening deadly heat waves, droughts, and floods. According to the authors, the people who perished in those events should be viewed as casualties of climate change.
Take the drought that gripped East Africa in 2011 and 2012. A 30 percent decline in rainfall over parts of Somalia and Kenya exacerbated what had already been several years of dryness, slashing farm yields. Between 50,000 and 100,000 people died as a result, more than half of them young children. The drought also triggered a refugee crisis, as residents of the parched regions fled to find food and water. Climatologists have shown through observations and computer modeling that increased sea-surface temperatures significantly worsened the drought. The excess heat in the ocean at the time cannot be attributed to the naturally occurring El NiÃ±o Southern Oscillation, marking climate change as the culprit in the deaths.
The East African drought is just one of many examples of deadly dry periods attributable to climate change. It also caused or intensified heat waves in Europe in 2003, in Russia in 2010, in the United States in 2012, and in Australia, China, Japan, and Korea in 2013. Floods in the United Kingdom in 2011 and heavy rains in the United States and India in 2013 were also due to climate change. And those are just the proven climate change catastrophes. Our warming planet is a suspect in many other extreme-weather events, but scientists are still working to confirm the connection.
The paper’s focus on the present day is critical, since people have trouble putting a value on hypothetical lives. Climate change’s victims aren’t hypothetical. There are already climate change widows, climate change orphans, and parents who have lost small children to anthropogenic climate change.
Droughts, heat waves, floods, hurricane intensification…these are the obvious consequences of climate change. But, as the expert panel emphasizes, raising the planet’s temperature a few degrees will have vast indirect effects as well — some of which you may not even have considered.
For example, one of the most important public-health innovations of the past few centuries is keeping our bodily waste separate from our drinking water. (Why did it take us so long to think of this?) Heavy rains and flooding can wash that divide away, as sewers overflow and waste travels unimpeded into waterways. The problem is particularly acute in the developing world, where the wall of separation is less formidable.
Cholera, a waterborne disease that thrives when infected wastewater makes its way into the drinking-water supply, already affects more than three million people a year and kills over 100,000, many of them children. Although no one can say precisely how many more people will contract cholera as climate change progresses, those numbers are almost certain to rise.
Other infectious diseases will also expand. Climate change will broaden the habitable territory of mosquitoes, which carry malaria, dengue fever, chikungunya, and a variety of other deadly diseases. Ticks, which spread their own catalogue of infectious maladies, are also moving into new areas.
Air pollution will intensify, too. Ground-level ozone forms more easily in hotter climates, and models suggest that climate change will make the problem worse during summers in the United States and Europe. The Lancet’s panel cited the work of NRDC scientist Kim Knowlton, whose 2004 paper indicated that ozone-related deaths would rise 4.5 percent between 1990 and 2050, an increase entirely attributable to climate change.
Now let’s talk about poverty. One of the most fraught and complex climate change discussions is how carbon emissions cuts will affect the poor. Fossil fuels are a cheap and readily available energy source that have helped bring millions of people out of poverty. Even today, three billion people burn wood or animal dung to cook their food, and the resulting soot badly damages their health. Natural gas would immediately improve their lives, and we cannot forget those people as we plan to transition away from fossil fuels.
Today’s paper reminds us, however, that there are moral considerations on both sides of the equation. A two-degree Celsius increase in temperature could decrease maize production in Africa by as much as 3.4 percent, which would raise food prices and push many people closer to starvation. By the end of the century, climate change will expose hundreds of millions of additional people to drought. Depriving the poor of fossil fuels is a problem, but failing to protect them from global warming could be even worse.
“Preventable” is one of the most damning words in the medical lexicon. It’s the doctor’s way of saying that someone screwed up — a person died for no good reason. The new paper in The Lancet argues at length that climate change deaths are preventable, and we ought to stop pretending they’re acts of God.
“The central finding from the commission’s work is that tackling climate change could be the greatest public-health opportunity of the 21st century,” the panel writes. That’s the nicest possible way to say it.
The preventive measures aren’t complicated, although we have to do more than simply cut down on carbon emissions. The panel emphasizes the need for early-warning systems for extreme-weather events and improvements in emergency preparedness. (Remember Hurricane Katrina?) We will likely need to build dams, dykes, and levees to hold back rising seas and protect our communities, as well as adjust city planning to minimize the urban heat island effect by covering structures with vegetation where possible, increasing shaded areas, and adding reflective surfaces. Water infrastructure could use an upgrade, too. Agricultural research must expand to help farm production keep pace with the challenges of a warming world and the weather patterns that come with it. The international community should also develop contingency plans to deal with climate refugees. The list is long but manageable. (Plus, we don’t have any choice.)
It will be interesting to see how climate change deniers respond to this group of doctors who are prescribing preventive medicine for climate change. Polls suggest that nearly three in four Americans favor increased investment in disease prevention, and these high levels of support cut across traditional regional and political divides. Climate change is a large-scale disease — a sickness of the planet that will trigger symptoms in communities and individuals. Shouldn’t we take preventive action?
Finally, I’m curious to see how the medical community, in general, fares against climate change deniers. Last week, many politicians who are otherwise ideologically aligned with the Vatican attacked Pope Francis for speaking up against climate change.
Doctors, however, are held in even higher esteem. A 2014 Gallup poll showed that 46 percent of Americans rate the honesty and ethical standards of the clergy as “high” or “very high.” The rating for physicians was 19 percentage points higher. Attacking doctors is probably a losing political strategy. Especially for members of Congress — only 7 percent of Americans trust them.
Global warming causes sea level to rise in two ways. First, it melts ice sheets, glaciers, and sea ice. The melting ice flows into the ocean, increasing the total amount of water as well as sea level. Second, water expands as it heats. Therefore, a warmer ocean is a bigger ocean.
Since sea-level rise is one of the most certain and widely reported effects of climate change, climate deniers are keen to find evidence that it isn’t happening. They’ve seized on some admittedly confusing data in the last few years. Precise, satellite-based sea-level measurements began in 1993. Between then and approximately 2002, global mean sea level increased by an average of slightly more than three millimeters per year. However, in the ensuing decade, when climate change was supposed to be accelerating, global mean sea-level rise appeared to slow to slightly more than two millimeters per year—a deceleration of nearly 30 percent.
This kind of data is a dream for people who deny climate change. They use it in combination with the claim that global warming has “paused” in the last decade, arguing that measurements on the ground are inconsistent with climate change theory. Here’s noted climate change skeptic Judith Curry making that claim: “Once again, the emerging best explanations for the ‘pause’ in global surface temperatures and the slowdown in sea-level rise bring into question the explanations for the rise in both in the last quarter of the 20th century. And makes the 21st century of sea level rise projections seem like unjustified arm waving.”
This argument has always been badly flawed, because one of its pillars of evidence, the supposed “pause” in global warming, is a fantasy. Global temperature continues to increase rapidly. There is no pause.
Today, the second part of the two-pronged denier argument took a major hit. In a paper published in the journal Nature, a team of scientists based in Australia, the United Kingdom, and the United States showed that the widely reported slowdown in global sea-level rise was due to an error in instrumentation. When measuring sea-level change, previous researchers had failed to take into account that land also moves up and down.
When they corrected the sea-level measurements to reflect those “vertical land movements,” the authors found that the ocean rose more slowly in the mid-1990s than we previously thought. In fact, global mean sea-level rise may have been as low as 2.6 millimeters per year at the end of the last century, instead of a little over 3 millimeters as previously thought. If these data are correct, the ocean is rising faster today than it was when satellite measurements began in the 1990s—just like climate change science predicts.
Let me put that as simply as possible, so there’s no room for creative misinterpretation: Sea-level rise is accelerating. There is no disagreement between the theories and the measurements.
It’s important to keep in mind that sea level is a complicated phenomenon and incorporates many factors beyond air temperature. Natural changes in the atmosphere and ocean currents also play a role, so it wouldn’t be shocking if sea-level rise decelerated briefly. If that were to happen, it wouldn’t invalidate climate change theory.
But again, to be clear, that is not happening: Sea-level rise is accelerating. It is not decelerating.
Also, remember that long-term observations are key. In the past five millennia, scientists estimate that the sea has risen less than one millimeter per year on average, based on geological markers on coastlines. So, whether sea level rises 2.5 or 3.1 millimeters this year, it is rising much faster than it has in the past.