Unusually hot summers, and the destructive droughts and wildfires that follow, are the product of climate change, according to a study of recorded global temperature data by a prominent Nasa scientist.

The study uses recorded temperature data, rather than prediction models, to assert that climate change is responsible for recent extreme weather events including last year’s droughts in Texas and Oklahoma, the Russian heat wave in 2010 and the European heat wave in 2003.

The author of the study and head of Nasa’s Goddard Institute for Space Studies, Dr James Hansen, said: “We now know that the chances these extreme weather events would have happened naturally – without climate change – is negligible.”

Statistical data in the study shows that temperature extremes are becoming more frequent and more intense across the globe. This does not eliminate the possibility of cooler-than-average summers in the future, but it does mean that the probability of unusually warm summers has greatly increased, the report said.

By comparing temperature data from the past 30 years to the 30 years prior, Hansen and his colleagues say the data shows that temperature extremes have increased from affecting less than 1% of global land area to an estimated 10%. Hansen explained that increased greenhouse gas emissions “load the dice”, or make the occurrence of these extreme temperature events much more likely.

Hansen is a leading climate scientist but also a controversial figure. In an apparent reference to the Holocaust, he has referred to trains transporting coal to power stations as “death trains”. He has also been arrested four times on climate change protest demonstrations, but always when on leave from his government post.

Other scientists had mixed reactions to the study. Dr Myles Allen, head of the climate dynamics group at Oxford University, said the results of the study are “broadly in line” with recent similar papers. But he questioned the authors’ interpretation of the data, in particular the suggestion that the recent heatwaves must have been a consequence of global warming because their likelihood otherwise was very small.

“It is very hard to quantify with any confidence the absolute probability of a weather event occurring in a hypothetical pristine climate: the public understand that extreme weather events happen, and the rarer and more extreme the event, the harder it is to quantify the odds of it happening in any given year,” Allen said.

The study was conducted before the record-breaking heat this summer, which has seen a devastating drought in the US midwest and destructive wildfires in Oklahoma.

June marked the warmest 12-month period in the US since record-keeping began in 1895 and at least 170 all-time high temperature records in the US were broken or tied in June.

Globally, the month has had the all-time warmest averaged land surface temperature, and average global temperature across lands and oceans were the fourth warmest since record-keeping began in 1880.

Hansen said in a press conference that to combat the change there needs to be a global effort to phase out dependence on fossil fuels in the long run.

Hansen said: “Frankly, it would not be that difficult to do it if we put an honest price on fossil fuels,” and went on to advocate for something similar to a carbon tax where companies must pay a fee to account for their use of fossil fuels.

Hansen also addressed critics who evidence extreme weather events from the past, like the Dust Bowl in the 1930s, as an explanation for record temperatures being a part of earth’s natural cycle. Hansen said that example does not deviate from his study, because statistics show that significant weather events such as the Dust Bowl are now occurring at an increased rate.

Within the past 24 hours, torrential rains have caused massive flooding in Manila, bringing the sprawling capital of the Philippines to a standstill. Dr Mahar Lagmay, executive director of Project Noah, the country’s diasaster mitigation system, said rainfall in Metro Manila (the City of Manila and its surrounding areas) has surpassed the levels of Typhoon Ketsana, which devastated Manila in 2009 and resulted in hundreds of deaths.

Tens of thousands of people have been evacuated and 15 deaths have been reported so far. CNN claimed 500mm of rain have fallen in Manila over the past 48 hours, while according to an AFP report, a landslide buried four houses in a Manila slum area.

Schools, financial markets and government offices were closed on Tuesday as flooding on major roadways made travel impossible. Schools in affected areas will remain closed on Wednesday. Non-stop monsoon rains have left hundreds stranded on roads and the government has issued landslide warnings in provinces outside the capital. Roads have turned into rivers, and on some streets people could be seen floating on whatever they could find.

Jean Navarez of the state weather service said: “If we put it in a percentage, at least 50% of Metro Manila is flooded.” Benito Ramos, executive director of the national disaster risk reduction and management council said the continued floods were due to the fact that soil remains saturated after several days of continuous rain. He added that “the sea and the flood waters looked like one single body of water”.

Massive evacuation and relief efforts have been underway throughout Metro Manila and nearby provinces. According to Red Cross volunteer Benjo Ramos, whose team has rescued more than 92 people so far, water levels have reached nine to 15 feet in some areas. “Some are stranded on the second floor, some are losing their second floors [and] calling for help from the roofs of houses,” he said. “We are taking them from houses to shelters, and feeding them – all our teams are out.”

A local emergency response team led by Melvin Villaruz, a councillor for Pasig City, has already evacuated 300 families of “informal settlers” living along the Pasig river, a 27km waterway that winds through Metro Manila. These disadvantaged communities are living there illegally but have nowhere else to go. “It’s very bad,” he said. “Beside the river it’s flooded area. Half the Pasig [river] is almost near the neck.”

He added: “We take them to schools or gyms for safety. We also rescued 10 children who were living under a bridge on the river. We warned them what will happen if the river rises in a few hours.”

Flooded roads make it difficult to reach these areas. On the way to the river, Villaruz’s team rescued a family of eight (a grandmother, five children and two adults) who could not leave their homes because the water had reached shoulder level.

John Javellana, a photojournalist who has covered every major typhoon in the country in the past four years, is surprised at how victims are responding to the flood. He says they are more prepared, even though there was no official typhoon warning sent out by the weather service (the local news reported only an upgraded rainfall alert and a warning of flooding in low-lying parts and areas located near river channels ).

“It was a relief to see,” said Javellana. “Although not ideal yet, people co-operated more with rescue workers. During Typhoon Ondoy [Ketsana], many people were hesitant to leave until the last minute because they were afraid of losing belongings. Now if it’s only a forecast for heavy rains and the government says go, they do.”

Ramos also noticed a difference in today’s rescue efforts. “Everyone pitched in – military, local government, police, NGOs … This time, everything was more organised and obviously people had learned from past disasters.”

Evacuation centres were also very organised, with relief goods making it on time, said Ramos. “It’s by the book – we are prepared this time. But there is a lot more work to be done, more families to be saved; it’s not over yet.”