Record temperatures across much of the world over the past two weeks could make July the hottest month ever measured on Earth, according to climate scientists.

The past fortnight has seen freak heat in the Canadian Arctic, crippling droughts in Chennai and Harare and forest fires that forced thousands of holidaymakers to abandon campsites in southern France and prompted the air force in Indonesia to fly cloud-busting missions in the hope of inducing rain.

If the trends of the first half of this month continue, it will beat the previous record from July 2017 by about 0.025C, according to calculations by Karsten Haustein, a climate scientist at the University of Oxford, and others.

This follows the warmest-ever June, which was confirmed this week by data from the US space agency Nasa, following Europe’s Copernicus satellite monitoring system.

In response to the new numbers, Michael Mann, the director of the Earth System Science Center at Pennsylvania State University, tweeted: “This is significant. But stay tuned for July numbers. July is the warmest month of the year globally. If this July turns out to be the warmest July (it has a good shot at it), it will be the warmest month we have measured on Earth.”

The scientists stressed that this outcome is uncertain because conditions could change in the second half of the month, but it underscores a broader pattern of steadily rising temperatures caused by increasing emissions of carbon dioxide from power plants, deforestation, cars, planes and other sources.

Mann estimated the chance of a new record this month at about 50%. In the longer term, he said records would continually be broken. “We have shown in recent work that the record warm streaks we’ve seen in recent years cannot be explained without accounting for human-caused planetary warming. Those warm streaks are certain to not only continue but to worsen if we continue to burn fossil fuels and warm the planet.”

Nine of the 10 hottest years on record have occurred since 2000, according to the US National Oceanic and Atmospheric Administration. Data from the first six months of this year indicates this year has a 99.9% chance of entering the top five, according to Gavin Schmidt.

“It is clear that 2019 is shaping up to be a top-five year – but depending on what happens it could be second, third or fourth warmest. The warmest year was 2016, which started with a big El Niño, which we didn’t have this year, so a record year is not particularly likely,” he said.

Of the many recent temperature anomalies, perhaps the most remarkable was in the Canadian Arctic community of Alert, Nunavut, which hit a record 21C on 14 July, although temperatures at this time of year are usually just a few degrees above freezing.

Last month, France shattered its previous heat record during a heatwave across much of Europe that was made at least five times – and possibly hundreds of times – more likely by human-driven climate disruption, according to scientists.

Political leaders have failed to halt the rise in emissions that is behind global heating. On Tuesday, the UK environment secretary, Michael Gove, warned that time was running out to prevent a breakdown of the climate and natural life support systems. “These twin challenges of biodiversity and climate change are massive and urgent and interrelated. The action taken so far hasn’t been sufficient, but late as it may be, there is still time,” he warned. “The scale of action required may be daunting, but the need to act is imperative.”

The UK has avoided most of the extreme heat seen in Europe in elsewhere in recent weeks. The average temperature in the first two weeks of July was 15.1C, which equals the July average, though Mark McCarthy, the head of the Met Office’s National Climate Information Centre, said there might be a modest rise because the second half of the month is usually marginally warmer than the first.

Concerns about rising temperatures and their impact on health are growing. On Tuesday, the Red Cross launched a new Heatwave Guide to help urban planners and city authorities reduce the risks, which are particularly great for the elderly, very young children, pregnant women and people who are socially isolated.

“Heatwaves are one of the deadliest natural hazards facing humanity and the threat they pose will only become more serious and more widespread as the climate crisis continues,” said Francesco Rocca, the president of the International Federation of Red Cross and Red Crescent Societies.

Previous heatwaves have killed tens of thousands of people, including 2,500 in India in 2015 and 70,000 in Europe in 2003, according to the Red Cross.