UN Environment’s 2018 Emissions Gap Report takes a close look at the pledges that countries have made to reduce their emissions.

It calculates how far those pledges will go to prevent dangerous levels of warming, and it shows just how much more action is needed to keep us on a safe path. So what will happen to greenhouse gas emissions in the future? It all depends on how much countries choose to do to reduce their emissions. Scientists have modeled a number of scenarios, taking into account the climate pledges — known as “nationally determined contributions,” or NDCs — that countries committed to in the Paris Agreement on Climate Change.

What will happen to global greenhouse gas emissions if countries keep all of their climate promises? And what will happen if countries fall short?

The baseline scenario estimates what would happen to global greenhouse gas emissions in the absence of any climate policies since 2005.  

The current policy scenario takes into account all of the policies now in place, but assumes that no additional measures are undertaken.

The unconditional NDC scenario assumes that countries meet all of the climate pledges that have no conditions attached.

Under the conditional NDC scenario, it is assumed that countries achieve all of their climate pledges, including those with conditions.

If we want to prevent warming of 2°C by 2100, then we will have to make sure that our emissions output doesn’t exceed 40 gigatons of CO2 equivalent by 2030.

To limit warming to 1.8°C by the end of the century, emissions will have to be cut even further, not exceeding 34 gigatons of CO2 equivalent by 2030.

And to prevent 1.5°C of temperature rise by 2100, our total emissions will have to stay below 24 gigatons of CO2 equivalent.

To keep global warming well below 2°C, global greenhouse gas emissions will have to peak by 2020, and decline rapidly thereafter. At the moment, our greenhouse gas emissions show no sign of peaking. In fact, after holding steady from 2014 to 2016, global emissions went up again last year. But there’s reason for hope. If we act together — and if we act quickly — then it’s still possible for us to prevent dangerous levels of warming. All countries, whether developed or developing, have a role to play in this fight. And the good news is that it’s possible to reduce emissions without sacrificing economic growth.

A number of countries have already reached their peak emissions, and more are on track to do so soon.

The magnitude of emissions from China, the United States, and, to a lesser extent, India and Europe, dwarfs the rest of the world if we chart every country’s emissions since 1950.

In this grid, arranged geographically, each country’s individual trend is more apparent. This way, we can now discover
where emissions have peaked,
and where they haven’t peaked.

19 countries — including Germany, Norway and a number of former Soviet states — had already reached their peak emissions before 1990.

Of the 43 developed and emerging economies listed in Annex I of the Paris Agreement, all but one (Turkey) are expected to have peaked their emissions by 2020.

By 2030, up to 57 countries — representing 60% of global emissions — will have peaked their emissions, assuming those countries meet their commitments.

But these promises still fall short: even if countries keep all of their current commitments, global emissions will continue to rise.

All countries need to work to bring down their emissions, but the biggest impacts will come from the top four emitters — China, the United States, the European Union, and India — which together account for more than 56% of all the greenhouse gases that were emitted over the last decade.   If we act quickly, it’s still possible for us to meet the Paris Agreement’s more ambitious goal of limiting warming to 1.5ºC.

Which countries are the biggest emitters? And which countries are on track to meet their commitments?
Yes Uncertain No

Not every country is doing what it needs to bring emissions down and limit warming. Here, cells are sized according to each country’s emissions, so we can spot the biggest contributors.

China, the single biggest contributor, accounts for 27% of all emissions — although there are signs that the country could be nearing its peak.

The United States and the European Union are responsible for more than one-fifth of global greenhouse gas emissions. In the US, they have been falling on average since 2004.

India’s emissions represent 7.1% of the global total, and even though they’ll continue to grow as the country’s economy develops, its commitments are at least compatible with the 2ºC goal set in Paris.

Greenhouse gas emissions in Russia represent 4.6% of the global total and have grown by about 1% per year since 2014.

Even if countries follow through on all of their “unconditional” climate pledges, the planet’s average temperature will probably still rise by about 3.2°C by the end of this century, well beyond the goal of Paris Agreement. So where to go from here? The message is clear: countries will need to be much bolder in their climate commitments if we are to avoid crippling levels of climate change. They will also need to put in place smart domestic policies that can translate those commitments into real progress on the ground.

We have a lot to do, but the good news is that we’re already learning what works.

Ambitious policies that kickstart and sustain innovation can go a long way towards helping us close the emissions gap. Governments can lead the way by actively supporting innovation and shaping markets for new emissions-cutting technologies. Such policies can have an enormous impact, as we’ve seen with solar panels.

The total energy from solar panels installed around the world has soared in the last few years.

The actual growth in solar power wildly exceeded expectations.

The development of cutting-edge low-carbon technologies is critical to closing the emissions gap, but this won’t happen on its own. The 2018 Emissions Gap Report sets out five principles to help policymakers craft ambitious and effective policies to drive innovation — and bring it to market.

Cities, districts and provinces, as well as companies and major investors, can be critical to helping their countries achieve their emissions reductions targets. Cities can serve as testing grounds for innovative new policies. They can also be important advocates, pushing their national governments to take bolder action to protect the climate.

In September 2018, more than 4,500 mayors, governors, and business leaders gathered in San Francisco for the first-ever Global Climate Action Summit. The gathering galvanized some impressive announcements. Over 70 cities, including Los Angeles, Tokyo, and Mexico City, committed to becoming carbon neutral by 2050.

488 companies from 38 countries adopted emission reduction pathways in line with the Paris Agreement.

More than 60 state, regional, and city governments and multinational businesses pledged to make all of their vehicles emissions free.