A climate scientist who has warned about a grim “Hothouse Earth” scenario is back with a proposal about how to save the planet.

It’s a straightforward, five-part plan that he says could eliminate poverty and hunger while helping the planet at the same time.

But the plan requires unprecedented shifts in the way we do everything, from powering our lives to redistributing wealth.

There’s a lot of doom and gloom about the state of the planet.

Earlier this month, the UN’s Intergovernmental Panel on Climate Change (IPCC) released a report suggesting that by 2040, the world will be 1.5 degrees Celsius warmer than it was before we started burning fossil fuels like coal and gas for energy.

Other scientists have suggested the world could hit a tipping point that triggers a “hothouse” state, in which the Earth would shift from a self-cooling biosphere into a self-warming mode. That could make our planet 4, 5, or even 6 degrees Celsius warmer than it is today, triggering unprecedented natural disasters.

But scientists still harbour some hope.

This week, one of authors of that bleak “hothouse” report has co-authored a new one that models how the world and its people may fare in the coming decades. In brief, ecologist Johan Rockström, who directs the Potsdam Institute for Climate Impact Research in Stockholm, thinks there might be a way to cut global emissions while eliminating poverty and hunger and keeping the world cool enough to sustain future generations.

“This is actually quite uplifting,” Rockström recently told a crowd at the TED Conference New York Headquarters, before the report came out.

But the plan requires enormous shifts in the way we do everything, from how we distribute money to the ways we grow our food.

Here’s the five-part formula:

1. Cut global greenhouse-gas emissions in half every decade, starting in 2020

These emissions come from burning fossil fuels that power our cars, planes, buildings, and food supply; they’re the reason the atmosphere is trapping more of the sun’s heat than it used to. Rockström’s proposal to slash emissions rates in half every decade is a steeper target than the Paris climate deal called for – countries who signed that agreement vowed to cut emissions 40% by 2030 (or at least try to). President Donald Trump has promised to pull the US out of that deal; on Wednesday, the Environmental Protection Agency announced that the US reduced its emissions by just 2.7% last year.

2. Increase food chain system efficiency, from soil to table, by 1% every year

A massive shift in the way we produce, harvest, and consume food would apply to every piece of land and sea across the world. As the authors write, “at least 1% extra resource use improvement per year is required in the whole food chain, from soil to table.” This would be crucial, since droughts and extreme weather threaten crops as diverse as coffee, rice, wine grapes, and barley for beer.

3. Fundamentally shift the way we create new wealth and prosperity

“We’re quite clever at short-term lifting people out of poverty,” Rockström told Business Insider. But there’s a hidden cost in our current models of economic development: “the wealth that we’ve created in countries like the US, or my own home country Sweden, has occurred at the expense of the climate system,” he said.

As economies grow and people get richer, rising production and consumption mean that more coal, oil, and gas get burned. That activity emits more carbon dioxide.

“It occurs by eroding the resilience of the Earth system,” Rockström said. “That’s not only the climate system, that is losing biodiversity, it’s ruining the oceans, it’s deforestation, it’s risking the stability of the whole planet.”

Rockström proposes looking to some new development models that focus on community-level development and the use of local resources. These kinds of approaches are already in use in places like Ethiopia and Costa Rica.

4. Ensure the richest 10% of people on Earth don’t hold on to more than 40% of its wealth

Rockström’s plan also demands a dramatic reshuffling of the world’s cash. More taxes on top earners could pay for better infrastructure, while improvements in wages would be a welcome bump for middle class workers, many of whom haven’t seen their pay go up much since the 1970s. Some of that shared money would also get used for healthcare, while other funds could go to education and investments in more sustainable buildings and cities around the world.

Currently, the top 1% of people own nearly half of the world’s household wealth. According to Credit Suisse’s 2018 global wealth report, “the richest decile (top 10% of adults) owns 85% of global wealth, and the top percentile alone accounts for almost half of all household wealth (47%).” This is especially true in the US, which has more members of the 1% than any other country. Credit Suisse defines membership in the top 10% as having $US93,170 or more in net assets, while the top 1% has $US871,320.

5. Investing more in education, health, and family planning

In addition to improving people’s lives, this would help control population growth, as the Bill and Melinda Gates Foundation often points out. Letting more girls continue their education and receive wanted contraception would change the global demand for energy, food, travel, buildings, and all other resources on the planet.

It’s an aggressive solution, but it’s the only one the researchers think will kept the planet and its people healthy in the long run

The computer modelling system that these climate and welfare projections were based on is called Earth3. It’s a projection tool that factors in social and economic data from the past 40 years and couples that information with what we know about how the planet’s atmosphere, oceans, and land will likely react to greenhouse gas emissions.

This ambitious five-step global transformation wasn’t the first plan Rockström and his team of scientists tried out in Earth3.

Initially, they charted three other scenarios. First, they analysed what would happen to the Earth’s climate and its people if we change nothing about the way we do business. Second, they calculated what would happen if we accelerate economic growth. And third, they looked at how the world would fare if that economic growth were coupled with efforts to fund more education, clean water, food, and jobs.

But none of those more traditional trajectories worked out in the long run – they all made the Earth too hot. So Rockström and his colleagues landed on this model, which is more ambitious and far less tested.

They also discovered that the costs of this plan to society would be relatively small: by 2050, according to their estimate, GDP would be just one year behind where it would be if we continue on a business-as-usual path. And we’d probably make up for that loss in the long-term, they said, since we’d keep the planet from becoming a “hothouse.”

As the authors of the report argued, “most rational analysts” would agree that in the long run “the Earth’s life-supporting systems are worth it.”

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