The WHO estimates each excess death led to a loss of more than 22 years of life and warns the world must heed the lessons of the "tragedy" of these pandemic years. This year's report includes a section on climate change and health for the first time and calls for a "strengthened response".
Almost 15 million global excess deaths by the end of 2021 were caused by COVID
, according to figures released by the World Health Organisation (WHO).
It estimates a total of 336.8 million life-years were lost globally due to the pandemic which was declared in early 2020.
This means that, on average, each excess death led to a loss of more than 22 years of life, with the highest amount lost in people aged 55-64.
The figures, included in a new WHO report, are the clearest indication yet of the devastating legacy of the pandemic on a global scale.
Earlier this month the WHO decided to lower its highest level of alert for the virus, saying it was no longer a global health emergency - but warned "that does not mean COVID
-19 is over as a global health threat".
-19 has changed our world and it has changed us," it said, warning that the risk of new variants still remained.
The WHO's assessment of global health also calls for a worldwide response to the growing threat of non-communicable diseases (NCDs) such as cancers, heart disorders and diabetes - which it warns if left unchecked could account for 86% of all deaths by 2050.
Despite progress in medicine, NCDs now claim nearly three-quarters of all lives lost each year.
If this trend continues, NCDs are projected to account for about 86% of the 90 million annual deaths by mid-century, the WHO's World Health Statistics report warned.
It would mean 77 million annual deaths would be due to NCDs - an increase of nearly 90% since 2019.
The WHO calls for "decisive and collective" action to tackle what it describes as "an ever-increasing health threat for future generations".
WHO director-general, Tedros Adhanom Ghebreyesus, said: "The world must heed the lessons of the last two decades, including the tragedy of these pandemic years.
"One of the most important of those is the knowledge that we have it in our power to avoid unnecessary deaths and illness, and create stronger, more equitable and resilient health systems and societies."
There are also wider concerns about how the pandemic has exacerbated health inequalities and dented improvements in tackling Malaria, TB and so-called neglected tropical diseases.
This year's report includes a dedicated section on climate change and its impact on health for the first time and calls for a "coordinated and strengthened response".
"Climate change is one of the greatest health challenges of the 21st century," the report says.
"As climatic conditions change, we are witnessing more frequent and intensifying weather and climate events, such as storms, extreme heat, floods, droughts and wildfires.
"These weather and climate hazards affect health both directly and indirectly, increasing the risk of deaths, NCDs, the emergence and spread of infectious diseases, and health emergencies."
The WHO report says all aspects of health are affected by climate change - from clean air, water and soil to food systems and livelihoods - and warns that further delay in tackling global warming will increase health risks and undermine decades of improvements in global health.
In terms of estimating the future impact of climate change on health, it cited a recent report by the Intergovernmental Panel on Climate Change (IPCC) in which the UN climate scientists comprehensively reviewed current evidence and concluded that under a high emissions scenario there could be more than nine million climate-related deaths each year by the end of the century.