Urgent Climate Change Message By Over 11,000 Scientists; Reduce Air Pollution To Slow Warming & Save “Millions Of Lives”

Some 11,258 scientists from 153 countries have issued a sharp warning in the journal BioScience, about the climate emergency faced by the global community.

The scientists calls for “bold and drastic transformations” in six key areas to pull earth from the precipice of potentially catastrophic deterioration in basic life support systems. Their prescription includes: a rapid shift of economies from fossil fuels to renewables; reduced emissions of short-lived climate pollutants like methane and black carbon (soot) that could slow short-term warming trends “while saving millions of lives” from air pollution; restoration of degraded natural ecosystems from coral reefs to savannas; shifting to mostly plant-based foods; reduced over-consumption of materials and minerals; and stabilization of population growth with access to family planning services, progress in gender equity, and universal primary and secondary education including for girls and young women.

The article published on Monday, a month ahead of the 25th Climate Conference (COP 25) in Madrid, carries a particular note of urgency in light of the large number of signatures by scientists, who normally frame their views in cautious, incremental terms.

“Scientists have a moral obligation to clearly warn humanity of any catastrophic threat and to “tell it like it is.” On the basis of this obligation and the graphical indicators presented below, we declare, with more than 11,000 scientist signatories from around the world, clearly and unequivocally that planet Earth is facing a climate emergency,” states the article published on Tuesday.

Earth’s Vital Signs in Red Zone

The scientists note that average global temperature increases are alone insufficient to capture the dimensions of the problems faced. They point to a range of “concurrent trends in the vital signs of climatic impacts” that represent a “suite of graphical vital signs of climate change over the past 40 years”.

These include: continued increases in atmospheric CO2, concentrations; in greenhouse gas emissions (CO2, methane, and nitrous oxide); and a particularly ominous 2019 spike in CO2.

Monthly mean carbon dioxide measured at Mauna Loa Observatory, Hawaii. The carbon dioxide data ([black] curve), measured as the mole fraction in dry air, on Mauna Loa constitute the longest record of direct measurements of CO2 in the atmosphere. […] The [black line represents] the monthly mean values, centered on the middle of each month. The [red line represents] the same, after correction for the average seasonal cycle. The latter is determined as a moving average of SEVEN adjacent seasonal cycles centered on the month to be corrected, except for the first and last THREE and one-half years of the record, where the seasonal cycle has been averaged over the first and last SEVEN years, respectively. Source: https://www.esrl.noaa.gov/gmd/ccgg/trends/
In addition, global ice cover “has been rapidly disappearing, evidenced by declining trends in minimum summer Arctic sea ice, Greenland and Antarctic ice sheets, and glacier thickness worldwide. Ocean heat content, ocean acidity, sea level, area burned in the United States, and extreme weather and associated damage costs have all been trending upward… Climate change is predicted to greatly affect marine, freshwater, and terrestrial life, from plankton and corals to fishes and forests (IPCC 20182019). These issues highlight the urgent need for action,” the scientists state.

“Profoundly troubling signs from human activities include sustained increases in both human and ruminant livestock populations, per capita meat production, world gross domestic product, global tree cover loss, fossil fuel consumption, the number of air passengers carried, carbon dioxide (CO2) emissions, and per capita CO2 emissions since 2000,” they add.  There are also positive trends, such as declines in global fertility rates, increased solar and wind power production, reduced forest loss in the Amazon, and fossil fuel divestment.  But renewable power production still lags far behind that of fossil fuels, and annual fossil fuel subsidies remained greater than US$400 billion in 2018.

“To secure a sustainable future, we must change how we live, in ways that improve the vital signs summarized by our graphs. Economic and population growth are among the most important drivers of increases in CO2 emissions from fossil fuel combustion (Pachauri et al. 2014, Bongaarts and O’Neill 2018); therefore, we need bold and drastic transformations regarding economic and population policies. We suggest six critical and interrelated steps (in no particular order) that governments, businesses, and the rest of humanity can take to lessen the worst effects of climate change. These are important steps but are not the only actions needed or possible,” the scientists add. Those include:


“The world must quickly implement massive energy efficiency and conservation practices and must replace fossil fuels with low-carbon renewables (figure 1h) and other cleaner sources of energy if safe for people and the environment. We should leave remaining stocks of fossil fuels in the ground (see the timelines in IPCC 2018) and should carefully pursue effective negative emissions using technology such as carbon extraction from the source and capture from the air and especially by enhancing natural systems (see “Nature” section). Wealthier countries need to support poorer nations in transitioning away from fossil fuels. We must swiftly eliminate subsidies for fossil fuels and use effective  and fair policies for steadily escalating carbon prices to restrain their use.”

Short-lived pollutants

“We need to promptly reduce the emissions of short-lived climate pollutants, including methane (figure 2b), black carbon (soot), and hydrofluorocarbons (HFCs). Doing this could slow climate feedback loops and potentially reduce the short-term warming trend by more than 50% over the next few decades while saving millions of lives and increasing crop yields due to reduced air pollution (Shindell et al. 2017). The 2016 Kigali amendment to phase down HFCs is welcomed.”


“We must protect and restore Earth’s ecosystems. Phytoplankton, coral reefs, forests, savannas, grasslands, wetlands, peatlands, soils, mangroves, and sea grasses contribute greatly to sequestration of atmospheric CO2. Marine and terrestrial plants, animals, and microorganisms play significant roles in carbon and nutrient cycling and storage. We need to quickly curtail habitat and biodiversity loss (figure 1f–1g), protecting the remaining primary and intact forests, especially those with high carbon stores and other forests with the capacity to rapidly sequester carbon (proforestation), while increasing reforestation and afforestation where appropriate at enormous scales. Although available land may be limiting in places, up to a third of emissions reductions needed by 2030 for the Paris agreement (less than 2°C) could be obtained with these natural climate solutions (Griscom et al. 2017).”


“Eating mostly plant-based foods while reducing the global consumption of animal products (figure 1c–d), especially ruminant livestock (Ripple et al. 2014), can improve human health and significantly lower GHG emissions (including methane in the “Short-lived pollutants” step). Moreover, this will free up croplands for growing much-needed human plant food instead of livestock feed, while releasing some grazing land to support natural climate solutions (see “Nature” section). Cropping practices such as minimum tillage that increase soil carbon are vitally important. We need to drastically reduce the enormous amount of food waste around the world.”


“Excessive extraction of materials and overexploitation of ecosystems, driven by economic growth, must be quickly curtailed to maintain long-term sustainability of the biosphere. We need a carbon-free economy that explicitly addresses human dependence on the biosphere and policies that guide economic decisions accordingly. Our goals need to shift from GDP growth and the pursuit of affluence toward sustaining ecosystems and improving human well-being by prioritizing basic needs and reducing inequality.”


“Still increasing by roughly 80 million people per year, or more than 200,000 per day (figure 1a–b), the world population must be stabilized—and, ideally, gradually reduced—within a framework that ensures social integrity. There are proven and effective policies that strengthen human rights while lowering fertility rates and lessening the impacts of population growth on GHG emissions and biodiversity loss. These policies make family-planning services available to all people, remove barriers to their access and achieve full gender equity, including primary and secondary education as a global norm for all, especially girls and young women (Bongaarts and O’Neill 2018).”


Image Credits: blog.oup.com, Bioscience.

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