John Englander is president of the International Sea Level Institute and author of “High Tide on Main Street.”

Indonesia made a stunning announcement this week that it will relocate its capital from Jakarta. The decision validates decades of warnings about the city’s catastrophic flood risk due to sinking land and rising seas. While Jakarta is especially vulnerable to the threat of rising seas, it serves as a profound wake-up call for hundreds of major cities, Washington included.

In making his decision, Indonesian President Joko Widodo said that the move is necessary, given that the city can no longer support its massive population in the face of environmental threats, as well as concerns of traffic congestion and water shortages. Surely at the top of his concerns is the fact that the city is sinking, a phenomenon known as subsidence. In the past 30 years, Jakarta sank more than 10 feet — a problem made only worse as the world’s great ice sheets melt.

Jakarta is an extreme case, but it is by no means unique. In the United States, major cities such as New Orleans and Norfolk are also subsiding, though not nearly as fast. Even still, all coastal cities must face up to the reality of rising seas. There is no time to waste in planning and adapting to this threat.

Although Miami is often cited as the city most at risk, there are many highly vulnerable — and highly populous — cities around the world, including Mumbai and Calcutta, India; Shanghai; Lagos, Nigeria; Manila; Dhaka, Bangladesh; Bangkok; Copenhagen; Tokyo; London; Houston; and Tampa. In fact, thousands of coastal cities and rural communities globally are not only at risk, but already experience increased flooding during extreme high tides, often referred to as “king tides.”

The swelling oceans demand that we start designing for and investing in the future now. The latest projections for average global sea-level rise this century range from about three feet to as much as eight. Keeping it to the lower part of that range largely depends on extreme global efforts to reduce greenhouse gases far beyond current efforts. But even a one-foot rise in sea level can dramatically increase coastal flooding. Hundreds of millions of people and trillions of dollars of assets are at risk.

Indonesia’s decision to be proactive is something all coastal cities should do, what I call “intelligent adaptation.” Instead of spending hundreds of millions of dollars on futile efforts to protect Jakarta from the dozen rivers that run through it — extending fragile walls never engineered to cope with the present threat — it will now start investing in a new capital city that has a sustainable future.

Meanwhile in the United States, the U.S. Army Corps of Engineers recently announced that the combination of rising seas and subsidence will render the $14 billion fix to New Orleans’s levees inadequate in just four years. Clearly, we need a new strategy, too.

Aggressively reducing carbon emissions could avert the worst scenarios, but sea-level rise probably cannot be stopped this century. The planet has already warmed almost 2 degrees Fahrenheit, which means ice sheets and glaciers will continue to melt for centuries.

Engineering for greater “resiliency” — the new buzzword — is a great idea to prepare for short-duration flood events such as from hurricanes. But preparing for rising sea level is different and requires adapting to a new normal.

Though it is tempting to procrastinate, cities would be smart to begin their adaptation planning now. By planning for rising sea levels, cities create confidence in their future. Adaptation can be a tremendous economic opportunity.

Coastal communities should be crafting 30-year master plans to positively address the threat, which could take many forms. For example, Washington is on the Potomac, a tidal river, and already experiences occasional flooding during extreme high tides and stormy weather. Rising seas will make that worse, but the city can probably protect itself with various forms of flood barriers on the river. Most vulnerable cities are not so fortunate and will need to look at a full range of options.

In Jakarta, the solution was to move the capital. Even that dramatic decision will not quickly solve the challenges for the 10 million residents. Yet it recognizes a new reality, allowing them to trulyinvest in the future. It’s time for all coastal communities to plan for the future.

The sea is rising. We must rise with the tide.

On 13 April, 2029, people looking towards the sky will see a speck of light streaking across it, which will quickly get brighter and faster. It will be travelling so fast that it will cross the width of the Moon in a minute and be as bright as stars in the sky.

Scientists have named the rock Apophis, after the Egyptian god of chaos.

The glowing speck will be a huge asteroid, 340 meters across, that Nasa is already preparing to watch as it flies past Earth. The space agency says that it will fly far enough away as to be harmless – at a distance of 19,000 miles – but that is as close as some of the spacecraft that flies past Earth.

It is also close enough that researchers will be able to get an unprecedented look at the asteroid itself. They will be able to see the rock in sharp detail, allowing them to observe it in new ways.

It’s very rare for asteroids of this size to go past so close. Scientists have seen smaller asteroids at a closer distance, but something of such a colossal size are far fewer in number, Nasa said.

“The Apophis close approach in 2029 will be an incredible opportunity for science,” said Marina Brozović, a radar scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, who works on radar observations of near-Earth objects (NEOs). “We’ll observe the asteroid with both optical and radar telescopes. With radar observations, we might be able to see surface details that are only a few meters in size.”

Scientists meeting this week at the 2019 Planetary Defense Conference in College Park, Maryland – where they have also been role-playing a fictional collision with an asteroid – have been discussing how to watch the asteroid and missions that could be sent out to meet it.

It will first be visible to the naked eye when it arrives in the night sky over the Southern Hemisphere, shooting across the east coast to the west coast of Australia. It will make its way around the world, cross the Indian Ocean on its way to the US.

Its closest approach will be over the Atlantic Ocean, as the evening arrives in the US. It will move so fast that it will cross the ocean in just an hour, and will then fly off into space.

Apophis was first spotted by astronomers at the Kitt Peak National Observatory in June 2004. Soon after spotting it, further work was derailed by technical and weather problems.

But it was spotted again by scientists in Australia, who calculated it had a 2.7 per cent chance of hitting Earth when it passed by in 2029. It has since been watched more closely and that possibility has been ruled out.

Researchers now say that further work and calculations show there is only a 1 in 100,000 chance the asteroid will hit Earth. But further work will be required to rule out future impacts.

When it arrives in 2029, that observation will continue. Scientists hope to learn more about the asteroid’s size, shape, composition and maybe its interior.

At the conference, researchers discussed questions such as whether the asteroid will affect Earth’s gravity, whether they will be able to peer inside and whether it should be met by a spacecraft.

“We already know that the close encounter with Earth will change Apophis’ orbit, but our models also show the close approach could change the way this asteroid spins, and it is possible that there will be some surface changes, like small avalanches,” said Davide Farnocchia, an astronomer at JPL’s Center for Near Earth Objects Studies (CNEOS), who is co-chairing the April 30 session on Apophis with Brozović.

And researchers hope that the work they do on this flyby could protect us if any other asteroid were to come towards Earth.

“Apophis is a representative of about 2,000 currently known Potentially Hazardous Asteroids (PHAs),” said Paul Chodas, director of CNEOS. “By observing Apophis during its 2029 flyby, we will gain important scientific knowledge that could one day be used for planetary defense.”

The Independent

Hate to sound like a broken record, but we just set a scary new CO2 record