Climate change is the Pacific is no laughing matter.

Just over a week ago, the Prime Minister Tony Abbott and Minister for Immigration Peter Dutton were caught out laughing and joking about sea-level rise threatening Pacific Islanders’ home. They pair have since apologised – but as Richard Marles writes today, climate change in the Pacific is not a laughing matter.

The 45 minute drive from the airport to Betio on South Tarawa quickly clarifies what the issue of climate change means for the coral atoll nation of Kiribati.

You pass through an area inhabited by 50,000 people on a thin strip of land. In places the width of the road is the width of the island. At most points the sea is visible from both sides of the car. And despite being in the middle of the Pacific, a long way from the nearest million person city, this place is crowded. Every square inch of soil is being used. Every section of ground is precious.

On reaching your destination you are told that along the way you drove over the highest mountain in Tarawa. But you needed to be told because measuring a full three metres it was a literal hump in the road. You are also told that just the smallest rise in sea levels will ruin this place. But by now that has become abundantly clear.

Tarawa is the capital of Kiribati. It is a magnificent coral atoll surrounding a turquoise lagoon sixty kilometres in diameter. From the air it is a picture of paradise. Over the years it has been the destination for significant internal migration, so that half the country’s population now live there. Accordingly, the islets of South Tarawa are the most densely populated of the Pacific. The islet of Betio at the end of the atoll chain (the scene of the Battle of Tarawa in WWII) is one of the most densely populated islands in the world.

If sea level rises occur, well before Tarawa becomes submerged it will be uninhabitable. Changing weather patterns, with more severe and frequent storms, give rise to tidal surges that inundate houses on a basis that becomes too regular for repair.

But it is access to water which is the biggest issue. South Tarawa has groundwater which has been the source of its water for millennia. When a storm occurs the groundwater can become salty but over time flushes out and is drinkable again. Yet now the frequency of storms and over-population is rendering large portions of the groundwater permanently saline. Already half the groundwater in South Tarawa is undrinkable.

The traditional welcoming ceremony in Kiribati involves drinking from the well of the host village. There is a special place where dignitaries are welcomed to the country in this way. I’ve seen this welcome for both Ban Ki-moon and former Governor-General Quentin Bryce. But because the well at this point is now spoilt it is a ceremony that takes place using coconut juice. The alteration of this ancient and sacred custom is a particularly poignant indication of the effects of climate change.

The situation is even more fragile for Funafuti, the capital of Tuvalu. It has no groundwater, and so drinking water has always been based on the collection of rain. This has been a sustainable practice based on highly predictable weather patterns. But even with the provision of water tanks, largely through Australian aid, the total storage capacity of the island amounts to about six weeks’ worth of water.

At the end of 2011 the country experienced just the slightest change in rainfall. But for the Tuvaluans this was the equivalent of the most severe drought. Water levels declined to just a few days’ supply, forcing Australia and New Zealand to fly in emergency reserves of water.

These nations are based on the sea. It has been the source of their food, their recreation, and their culture. It has been a source of security. But when that very same source becomes the harbinger of life’s greatest threat the impact on the nation’s psyche is palpable.

For President Anote Tong of Kiribati the issue of climate change has defined his presidency. It requires him to make decisions that we can barely imagine. He once told me that maybe, just maybe, you could engineer sea-walls and other barriers to fortify some of the country’s hundreds of islands. But you could not do it for all of them. So which do you choose. How do you tell one community they can remain while another must end. It is an appalling situation.

Anote Tong is a great statesman. Half an hour with Anote and you see the politics of climate change in a totally different light. Half an hour with Anote and his governance reality becomes shocking. Half an hour with Anote and being a citizen of the country with the highest per capita carbon emissions in the world leaves you feeling that Australia has a particular responsibility to act.

Whatever else this situation may be, it most certainly is not a laughing matter.

Richard Marles was the Parliamentary Secretary for Pacific Island Affairs from 2010-2012.