Rich polluting countries which are predominantly to blame for the “dystopian” climate breakdown have broken their promises to reduce emissions and help developing countries adapt to global heating, according to Pakistan’s minister for climate change, who said reparations were long overdue.

More than 1,200 people are dead and a third of Pakistan is under floodwater after weeks of unprecedented monsoon rains battered the country – which only weeks earlier had been suffering serious drought.

In an interview with the Guardian, the climate minister, Sherry Rehman, said global emission targets and reparations must be reconsidered, given the accelerated and relentless nature of climate catastrophes hitting countries such as Pakistan.

“Global warming is the existential crisis facing the world and Pakistan is ground zero – yet we have contributed less than 1% to [greenhouse gas] emissions. We all know that the pledges made in multilateral forums have not been fulfilled,” said Rehman, 61, a former journalist, senator and diplomat who previously served as Pakistan’s ambassador to the US.

“There is so much loss and damage with so little reparations to countries that contributed so little to the world’s carbon footprint that obviously the bargain made between the global north and global south is not working. We need to be pressing very hard for a reset of the targets because climate change is accelerating much faster than predicted, on the ground, that is very clear.”

The extent of Pakistan’s flood damage is unprecedented.

An area the size of the state of Colorado is inundated, with more than 200 bridges and 3,000 miles of telecom lines collapsed or damaged, Rehman said. At least 33 million people have been affected – a figure expected to rise after authorities complete damage surveys next week. In the Sindh district, which produces half the country’s food, 90% of crops are ruined. Entire villages and agricultural fields have been swept away.

The main culprit is unprecedented relentless torrential rain, with some towns receiving 500 to 700% more rainfall than normal in August. Large swaths of land are still under eight to 10 ft of water, making it extremely difficult to drop rations or put up tents. The navy is carrying out rescue missions in normally arid areas where boats have never been seen, according to Rehman.

“The whole area looks like an ocean with no horizon – nothing like this has been seen before,” said Rehman. “I wince when I hear people say these are natural disasters. This is very much the age of the anthropocene: these are man-made disasters.”

Many have fled inundated rural areas looking for food and shelter in nearby cities which are ill-equipped to cope, and it is unclear when – or if – they will ever be able to go back. The total number of people remain stranded in remote areas, waiting to be rescued, remains unknown.

The water will take months to drain, and – despite a brief pause in the downfall – more heavy rain is forecast for mid-September.

Rehman, who was named minister for climate change in April amid a political and economic crisis that saw the ousting of the prime minister, Imran Khan, has said the government was doing everything possible but rescue and aid missions had been hampered by ongoing rain and the sheer scale of need.

While sympathetic to the global economic challenges caused by the Covid pandemic and war in Ukraine, she was adamant that “richer countries must do more”.

“Historic injustices have to be heard and there must be some level of climate equation so that the brunt of the irresponsible carbon consumption is not being laid on nations near the equator which are obviously unable to create resilient infrastructure on their own,” she said.

There are also growing calls for fossil fuel companies – making record profits as a result of Russia’s war in Ukraine – to pay for the damage caused by global heating to developing countries.

Rehman said: “Big polluters often try to greenwash their emissions but you can’t walk away from the reality that big corporations that have net profits bigger than the GDP of many countries need to take responsibility.”

The annual UN climate talks take place in Egypt in November, where the group of 77 developing countries plus China, which Pakistan currently chairs, will be pushing hard for the polluters to pay up after a year of devastating drought, floods, heatwaves and forest fires.

Pakistan is one of the most vulnerable countries in the world to global heating, and the current catastrophic floods come after four consecutive heatwaves with temperatures topping 53C earlier this year.

It has more than 7,200 glaciers – more than anywhere outside the poles – which are melting much faster and earlier due to rising temperatures, adding water to rivers already swollen by rainfall.

“We’re going to be very clear and unequivocal about what we see as our needs and due, as well as where we see the series of larger global targets going. But loss and danger to the south which is already in the throes of an accelerated climate dystopia will have to be part of the bargain driven at Cop27,” she said.

Richer polluting countries have so far been slow to cough up pledged money to help developing countries adapt to climate shocks, and even more reluctant to engage in meaningful negotiations about financing loss and damage suffered by poorer nations like Pakistan which have contributed negligibly to greenhouse gas emissions.

Discussion about reparations has been mostly blocked, leaving vulnerable countries like Pakistan “facing the brunt of other people’s reckless carbon consumption”.

“As you can see, global warming hasn’t gone down – quite the opposite. And there is only so much adaptation we can do. The melting of glaciers, the floods, drought, forest fires, none will stop without very serious pledges being honoured,” said Rahman.

“We are on the frontline and intend to keep loss and damage and adapting to climate catastrophes at the core of our arguments and negotiations. There will be no moving away from that.”