'We are walking when we should be sprinting': Report charts escape from climate disaster

The international group of climate scientists studying the impacts of and solutions to global warming released their latest synthesis report Monday, adding to a long series of scientific reports published by the group since the first was released in 1990.

Their conclusions underscore that the effects of climate change will continue to worsen, with reduced water availability and food production, increased risk of pandemics, malnutrition, displacement and associated mental health impacts, declining biodiversity and ecosystem functioning in terrestrial, freshwater and marine systems, and a growing likelihood of wildfires, flooding, extreme weather and expensive damage to infrastructure and buildings.

"It warns that the pace and scale of what has been done so far and currently are insufficient to tackle climate change. Rapid and sustained emissions reductions and accelerated adaptation action is required within this decade to address change," said Hoesung Lee, who chairs the United Nations' Intergovernmental Panel on Climate Change. "We are walking when we should be sprinting."

The report synthesizes knowledge compiled in the current sixth assessment cycle's three main working group reports and three special reports. It "stands on the shoulders of giants" to bring not only a warning, but new insights, perspectives and hope, Lee said in a news conference Monday morning.

It emphasizes that human influences are to blame for many of the consequences, particularly the increase in heat extremes, ocean acidification, sea level rise and glacier melt. Worsening drought, fires, flooding and precipitation are exacerbated by humans burning fossil fuels, but to a lesser extent.

The report also outlines a pathway forward, through the turmoil. It calls for net zero carbon dioxide emissions by 2050 for a chance at staving off the worst impacts by keeping average warming under 1.5 degrees Celsius, about 2.7 degrees Fahrenheit, or by 2070 for a chance to limit the average increase to 2 degrees Celsius. Either timeline is ambitious given past progress toward net zero and the current reliance of global energy production on the burning of fossil fuels, which release heat-trapping greenhouse gases like carbon dioxide into the atmosphere.

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The IPCC scientists see possibilities to achieve this goal with "rapid, deep and in most cases immediate greenhouse gas emission reductions," the report reads. Among the most promising mitigation options are scaling up solar and wind energy infrastructure, which are also some of the most affordable solutions. Arizona stands to play a large role in expanding the solar energy grid, with abundant sunshine and real estate on rooftops and open land.

It will be important to phase out coal and reduce methane emissions from oil and gas development, the report states. Bioelectricity, geothermal, hydropower and nuclear could be good, if expensive, energy alternatives. Carbon capture could provide a small but pricey margin of error while in the transition to renewables. Reducing the conversion of natural systems and enhancing carbon sequestration in agriculture are also essential steps toward a carbon neutral society. Improving the efficiency of buildings, vehicles, public transit, shipping, aviation and recycling systems will also be required.

All of these solutions are already possible with existing technology. But it will be important to implement them now, as the effective window for some of these actions is already closing.

"Adaptation options that are feasible and effective today will become constrained and less effective with increasing global warming," the report reads.

Rich nations must lead

The need for climate justice, or action to soften the disproportionate impact of climate change on already marginalized populations that have generally contributed less to the problem, is a key theme of the synthesis report.“Almost half of the world’s population lives in regions that are highly vulnerable to climate change. In the last decade, deaths from floods, droughts and storms were 15 times higher in highly vulnerable regions,“ Aditi Mukherji, director of climate adaptation and mitigation at the International Water Management Institute and one of 93 authors of the report, said in a press release.

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Up to 45% of global emissions are generated by just 10% of high-consumption households, the report found, while the bottom 50% contribute only 15% of emissions. Less developed nations, low-lying islands and poor communities with low per capita consumption rates and limited ability to adapt are expected to weather some of the harshest impacts of worsening storms, drought, crop failure and heat. A certain number of these events are already "baked in" to the future given past emissions. But there is still time to limit the damage, the scientists assert.

Rich nations, which have historically emitted the most by burning fossil fuels for energy and transportation, will be responsible for the lion's share of these cuts, owing to their still-high emissions and financial capabilities to make the infrastructure and lifestyle changes necessary to help reach the global target. In an address Monday, U.N. Secretary General António Guterres called for more affluent G20 countries to strive for carbon neutrality by 2040, a decade ahead of the global goal.

"Some parts of countries or regions must have that global net zero goal much earlier than 2050," Lee agreed. "They have the technology, finance and, I hope, political will. Therefore, they are in much better shape than other parts of the world to be on the trajectory toward the carbon neutrality by 2050."

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Lee also emphasized that scientists and leaders are not only talking about future impacts. The world's warming climate is already undermining livelihoods, damaging the global economy, challenging health care and threatening the ecological functioning of humanity's natural life support system.

"Every increment of warming will lead to rapidly escalating hazards and widening regional differences," he said.

“We live in a diverse world in which everyone has different responsibilities and different opportunities to bring about change," Lee said. "Some can do a lot while others will need support to help them manage the change.”