(CNN) Climate change is here and affecting our health, with extreme heat in particular also having effects on productivity, food supply and disease transmission, a new global report finds.
More people than ever are vulnerable to heat exposure globally, and numbers are rising, according to The Lancet Countdown on Health and Climate Change report by an international group of researchers, published Wednesday.
It comes just days after climate reports from the US government and the United Nations said that greater action on climate change is needed, with the UN report showing that in 2017, the highest levels of carbon were emitted globally.
Older people in Europe and the Eastern Mediterranean are most vulnerable because of larger aging and urban populations there.
The latest report estimates that 42% of over-65s in Europe and 43% in the the Eastern Mediterranean are already vulnerable to heat exposure; 38% of this group is vulnerable in Africa and 34% in Asia.
The report identified present-day changes impacting public health including lower productivity, decreased crop yields and spread of diseases such as dengue and cholera, said researchers from 27 global institutions, including universities and research centers, and the UN who put together the study.
Present changes in heat waves and labor capacity "provide an early warning of the compounded and overwhelming impact on public health that is expected if temperatures continue to rise," said Hilary Graham, professor of health sciences at the University of York in the UK, who participated in the report.
In 2017, 157 million vulnerable people were exposed to heat waves globally, and 153 billion hours of labor were lost due to heat exposure.
The United States has seen more frequent and longer-lasting heatwaves and a rise in vector-borne disease, with cases of diseases transmitted by mosquitoes, ticks and fleas such as Lyme disease and West Nile virus tripling between 2004 and 2016, according to the US Centers for Disease Control and Prevention.
Dr. Nick Watts, executive director of The Lancet Countdown, stressed that this is "not something that's happening in 2050 but something that we're already seeing today."
"High- and low- income countries are affected negatively," said Elizabeth Robinson, professor of environmental economics at the University of Reading, who was involved in the report. This just manifests in different ways, she added.
The second in a series, with the first released last year, the report analyzes 41 indicators tracking the link between climate change and health in five areas: climate change impacts, resilience for health, mitigation actions, finance and public engagement.
Robinson explained that there "is a lot of variability year on year," but "the trend appears to be upwards," indicating even more heat wave events in the future. Similarly, numbers of vulnerable people "are going up over time."
There have been some promising trends, like an increase in renewable energy, with jobs in that sector rising by 5.7% between 2016 and 2017, according to the report. But the investment in renewables "is not yet anything like what it would need to be if we are to get to the 1.5 degrees" -- a commitment agreed during the Paris Climate Agreement to limit average global temperature rise to 1.5 degrees Celsius from pre-Industrial Revolution levels, said Paul Ekins, professor of resources and environment policy at University College London, who was involved in the report.
Some positive trends were also identified in the form of coal phaseouts and cleaner, healthier transportation methods. But coal usage needs to be at 20% of 2010 usage levels by 2040 to meet targets, the report states.
Dr. Renee Salas, doctor of emergency medicine at Massachusetts General Hospital, who authored the American chapter of the Lancet report, said it delivers a message of hope, as action is happening, but she pointed out that "climate change is harming the health of this country now." This follows on from the outcome of the Fourth National Climate Assessment report published by the White House on Friday.
This year marked a record summer in many parts of the world, with much higher temperatures than most populations are used to. Watts highlighted a recent study suggesting that the 2018 heat waves across Europe were made twice as likely as a result of climate change. "Assigning attribution for every single event is difficult, but it's clear that these sorts of events are examples of what is likely to come if we don't rapidly respond to climate change," he said.
The research identified that the global population was on average exposed to a temperature increase of 0.8 degrees Celsius between 1986 and 2017. The global surface temperature change for this period was 0.3 degrees Celsius. This shows that "populations are aging, growing and migrating in to the areas worst affected by climate change," Watts explained.
Salas said that "We must take aggressive action to combat climate change today so that by the end of the century, we'll have saved thousands of lives each year, along with hundreds of billions of dollars in public health cost."
Small changes in temperature and rainfall will also help the spread of infectious diseases, the report found.
For example, the capacity of the dengue virus to spread has increased by 7.8% since the 1950s.
The seasonal capacity for the Aedes mosquito -- the primary species spreading Zika, dengue and chikungunya -- and its ability to spread have lengthened and strengthened, the report says.
2016 had the most dengue transmission on record, according to the report, and the spread is expected to rise in line with greenhouse gas emissions.
Kristie Ebi, a professor of global health at the University of Washington who also was involved in the report, said the geographic spread of the mosquito that can carry dengue, Zika and chikunguya has increased "dramatically with higher temperatures." She added that the researchers don't see the impacts individually but stressed the wide-ranging effects of climate change.
Levels of global cholera bacteria are also worrying. An increasing trend of rising suitability to Vibrio, the bacteria that can cause cholera and some other illnesses, has been observed globally. The United States witnessed a 27% increase in coastline areas that are suitable for Vibrio infections between the 1980s and 2010s.
We "can not ignore these challenges we are seeing," said Gina McCarthy, director of the Center for Climate, Health and the Global Environment at the Harvard T.H. Chan School of Public Health, who was not involved in report. She cited the California wildfires and the rise in vector-borne diseases.
A "lack of progress" in reducing emissions continues to endanger lives and public health care systems, according to the researchers.
Europe was the region with most premature deaths from ambient air pollution in the form of PM2.5 -- particulates smaller than 2.5 micrometers in diameter -- in 2015, followed by the Western Pacific and Southeast Asia, the report found.
Particulate matter can settle in airways and cause problems like cardiovascular disease, respiratory conditions and cancers, leading to premature death, according to the World Health Organization.
Paul Ekins, a professor of resources and environment policy at University College London who was involved in the report, stressed that "any notion we may have that somehow in Europe, we are kind of doing better than other regions should be displaced."
Extreme heat as a result of climate change cost the world 153 billion hours of work last year, the report found.
In China alone, 21 billion hours of work were lost to extreme heat in 2017, equal to 1.4% of the country's working population. Robinson said that rising temperatures have "a direct impact on labor."
The majority of labor hours losses occurred in more vulnerable regions such as India, southeast Asia and sub-Saharan Africa and South America.
After decades of global improvement in food security, the report shows that crop yields are falling in 30 countries, including Cuba, the UAE and Luxembourg.
In some countries, the difference between the actual crop yield achieved and the maximum crop yield proves that negative impacts of climate change cancel out technological improvements, according to a 2011 study, published in the Nature international journal of science.
Watts warned that the report shows over half -- 51% -- of 478 global cities surveyed stated that their public health infrastructure will be seriously compromised by climate change, by overwhelming services with new health threats or from extreme weather events directly threatening health services.
This means "systemic failure," Watts said, like the shutdown of a hospital.
Global spending on climate adaptation for health is at 4.8% -- too little to keep in line with the Paris Climate Agreement, the researchers say.
Europe and Southeast Asia are the biggest spenders, with low-income countries' funding too little to meet their needs, according to the report.
The report has upped the stakes for faster progress, Ekins said.
He believes that the findings represent a "worse outlook, because we weren't moving fast enough for 2 degrees," as agreed in the 2009 Copenhagen Climate Conference, "and we're definitely not moving fast enough for 1.5" degrees.
Watts noted that the Lancet Countdown report is not able to say in which direction the world is heading, but "whichever way we go, it ends up shaping the health profile of countries for the next century."