This flooding is part of a “king tide” – a tide higher than all others. When the sun, moon, and Earth are in alignment, and close to each other, the tides will have especially high amplitudes – that is, the highest high tides and the lowest low tides. If you want a general introduction to how tides work, check out this Crash Course Astronomy video.
So, with this week’s supermoon, the tides are especially strong – some of the strongest of the year. During high tide, salt water is sneaking through storm drains and spilling over seawalls all along our coasts.
This kind of flooding is often called “nuisance flooding” or “clear-day flooding” because it isn’t associated with storm surges or winds. But let’s be clear: this “nuisance flooding” is exactly how sea level rise works.
What’s more, these floods will become more common as sea level rises.
Last January was the hottest one on record, chasing the heels of the hottest year on record. This heat is impacting our coral reefs—the lifeblood of our oceans—and despite the promises of geoengineering and local conservation efforts, there’s no quick fix for these impacts.
These shattered records result from climate change fingerprinted onto a powerful El Niño, which warms the tropical Pacific Ocean and releases an unusual amount of heat into the atmosphere. This El Niño has changed patterns of temperature, drought, and floods across the world. It’s even been linked to the spread of mosquitoes that carry the Zika virus.
But, one of the biggest and most far-reaching impacts of El Niño lurks beneath the surface of our oceans: coral bleaching.
Coral bleaching often results from extreme ocean temperatures. Tiny algae live inside the tissue of the coral itself, generating nutrients from sunlight for its host. When the coral is “stressed” by high temperatures, it expels these algae, which turns the coral bone-white. While a coral can survive this bleaching for a few months, it’s starving, deprived of nutrients provided by its algae.
A bleached coral is more prone to disease and death. For example, heating of the tropical Atlantic in 2005 led to a bleaching event that killed nearly half of the Caribbean’s corals. Reefs are the foundation for healthy marine ecosystems. For example, they provide nurseries and breeding grounds for a quarter of the ocean’s fish, so the loss of these corals can decimate marine biodiversity.
Coral bleaching impacts humans as well. Reefs attract tourists, provide livelihoods for fishermen, and form living sea walls against erosion, generating an estimated $30 billion per year.
They’re also the sole subsistence for hundreds of thousands of Pacific Islanders. In the Marshall Islands of the western Pacific, reefs provide not only food, but also supply the coral sand that forms the islands themselves. Without its reefs, the entire nation will literally disappear. Researchers on a recent ecological survey of the Marshalls discovered the worst bleaching of its corals ever seen. It’s a foreboding finding for this fragile nation.
In short, the stakes are high.
The National Oceanic and Atmospheric Administration (NOAA) uses satellite measurements of ocean temperatures to predict bleaching. In 2014, it began monitoring an outbreak that escalated to the third-ever global coral bleaching event in October 2015. Reefs from Australia to Hawai’i to Florida turned white. El Niño is worsening and prolonging this problem. In fact, NOAA scientists just announced that this bleaching event is the longest one ever observed.
In the coming decades, ocean warming will usher in frequent, longer, and more severe bleaching, increasing coral death rates worldwide. This trend has led the Australian government to declare climate change the single biggest threat to its iconic Great Barrier Reef. That assessment likely holds for reefs worldwide.
So, what can we do to conserve our corals?
First, we have to recognize that temperature is not a reef’s only stressor. Runoff, chemical pollution, and invasive species can all decrease a coral’s ability to beat the heat. Maintaining clean oceans and limiting the spread of invasive species can encourage the growth of healthy corals. That’s been the management policy for the Great Barrier Reef, and it could work elsewhere.
While these actions could buy time for our reefs, they’re stop-gap solutions at best. Any attempt to minimize global coral bleaching has to address climate change. Because carbon dioxide also acidifies our oceans, solutions that cool the planet without cutting our carbon emissions won’t spare our reefs.
The Paris Climate Agreement is a step in the right direction. Now, it’s up to each nation to fulfill its commitment. As citizens, we must hold our government accountable to its promise to curb carbon emissions. It’s easy to fall into an “out of sight, out of mind” mentality, but ignoring the issue will only worsen it.
The solution won’t be easy, but without it, the future of our coral reefs will be far less colorful.
Fishermen off the coast of Peru have long noticed a warm current that appeared in the Pacific around Christmastime, and dubbed this phenomenon “El Niño,” after the young Christ. Today, “El Niño” refers to the pattern of unusually warm waters in the equatorial Pacific, which appears every 2-7 years and peaks in December.
Now, Christmas is almost upon us, and this year’s El Niño is expected to peak soon.
Surprise! Since then, the eastern Pacific has warmed even further, turning the 2015 El Niño into one of the strongest on record, second only to the one in 1997. You can explore current global ocean temperature anomalies at one of my favorite sites, here.
El Niño is changing temperature and precipitation patterns worldwide. In the next few months, El Niño is predicted to make the northern U.S. unusually warm (as my dad put it, “El Niño is bad news for northeast skiers”) and bring additional rainfall to the southern states. Check out the predicted impacts for your region here.
But El Niño impacts aren’t restricted to the U.S. In October, scientists at the National Oceanic and Atmospheric Administration declared the beginning of a global coral bleaching event, the third on record. Warm waters can stress corals, forcing out their symbiotic algae, bleaching the corals and effectively starving them. In 1997-1998, the largest El Niño on record caused a bleaching event that killed 16 percent of the world’s coral reefs. A similar event is now underway.
In fact, scientists at the National Oceanic and Atmospheric Administration say that the “hiatus”—a “pause” in global warming since 1998—may never have happened at all.
The paper, spearheaded by Thomas Karl and eight other NOAA researchers, was published in Science in late June. The authors found the “hiatus” in global warming might not be a real trend, but instead results from differences in ship and buoy measurements. Their findings have garnered the attention of other scientists, the media…and the US Congress.
The authors of this paper, and NOAA itself, were recently issued a subpoena by Lamar Smith, Chairman of the House Committee on Science, Space, and Technology. This subpoena seeks “all documents and communications referring or relating to corrections to sea temperature data from ships and buoys,” particularly emails between Karl and his collaborators.
“This subpoena appears to be furthering a fishing expedition,” Committee Ranking Member Eddie Bernice Johnson wrote in response to Smith. “Unfortunately, this is reflective of much of the Committee on Science, Space, and Technology’s ‘oversight’ work this Congress, and it is a disturbing trend for the legitimacy of this Committee.” Continue reading No, the “hiatus” doesn’t disprove global warming→
Why is climate change such a popular topic this month?
For the next two weeks, world leaders are meeting at the 21st Conference of the Parties (COP21) in Paris. Their mission: to reach a legally binding agreement to reduce international climate impacts. Unlike prior treaties, the COP21’s agreement could hold each nation accountable for reaching its promised carbon goal.
This agreement would aim to keep temperatures below the 2°C threshold to avoid the worst effects of climate change. However, many of the world’s most vulnerable nations think even more extreme measures won’t be enough.
“We all know, and must acknowledge, that the targets on the table now are not enough to limit warming to below 1.5 degrees, although they are a start in the right direction,” said President Loeak of the Marshall Islands. “If we’re to win the battle against climate change, the fossil fuel era must draw to a close, to be replaced by a clean, green energy future, free of the carbon pollution that is harming our health, stunting our growth, and suffocating our planet.”
The Marshall Islands sit less than six feet above sea level, which means that sea level rise could render them uninhabitable by the end of the century. So, for President Loeak, the stakes at COP21 are nothing less than the existence of his country. In that context, his go-for-broke call to end fossil fuel use seems more an act of desperation than one of extremism.