Six takeaways from the new climate report

Co-authored by Ilissa Ocko. Haz click aquí para leer en español.

The tangible effects of human-induced climate change are increasingly visible. A recent study, for example, found that the 2017 hurricane season was more intense as a result of our changing climate. Limiting global warming levels is essential to curbing the future impacts of climate change, but how much does an additional half a degree Celsius warming change our world?

The special report issued last night by the Intergovernmental Panel on Climate Change (IPCC) considers the impacts of 1.5 °C global warming above preindustrial levels, in contrast to 2 °C, and how this lower warming target can be achieved.The report was written by hundreds of scientists hailing from 40 different countries and based on research from thousands of scientific studies.

Here are 6 key takeaways from the new IPCC report:

1. When it comes to warming, 1.5 °C is much safer than 2 °C…but still riskier than the present.

Limiting warming to 1.5 °C compared to 2 °C has clear and considerable benefits, such as significantly reducing the risks of water scarcity, ill-health, food insecurity, flood and drought, extreme heat, tropical cyclones, biodiversity loss, and sea level rise.

Specifically:

• 10 million fewer people could be at risk from sea level rise
• Several hundred million people may avoid poverty susceptibility by midcentury
• World population exposed to water stress may be reduced by 50%
• Loss of 1.5 million tonnes of global annual catch for marine fisheries could be avoided
• 10-30% of coral reefs could be saved
• Permafrost area three times the size of Texas may be prevented from thawing
• The number of plant and animal species losing over half their habitat could be cut in half

However, the risks of these events in a 1.5 °C warmer world are still higher than today.

Adaptation needs are also more moderate at the 1.5 °C threshold, though adaptation limits (the point at which there are no feasible adaptation options available to avoid a given climate risk) may still be exceeded for threats including partial coral reef loss and stress to coastal-dependent communities.

If limiting global warming to 1.5 °C is feasible, it must be attempted utilizing mitigation and adaptation strategies designed with the goal of reducing global inequalities.

2. Remaining below 1.5 °C is possible, but requires deep and rapid emissions reductions from all economic sectors.

We are on pace to hit 1.5 °C global warming by 2030 at the earliest. To stay below this level, we must pursue each of the following:

• Decreased energy demand
• Lower emissions from energy supply
• Actively removing carbon dioxide from the atmosphere
• Fully decarbonizing the electricity sector by mid-century
• Ensuring renewables are the world’s dominant energy source by 2050
• Balancing land-use between sustainable agriculture practices, bioenergy production, and carbon storage

Emissions pathways consistent with limiting warming to below or near 1.5 °C require reaching net zero emissions around midcentury, and pursuing carbon dioxide removal mechanisms within this century. While the transitions in energy systems, land, transportation, infrastructure, and industries would be unprecedented in scale, they are not necessarily unprecedented in speed.

3. Cutting methane, black carbon, and other ‘super-pollutants’ vastly increases the chances of staying below 1.5 °C.

The likelihood that we will reach the 1.5 °C warming threshold is highly dependent upon the emission pathways of non-CO₂ climate pollutants, such as methane and black carbon. If the emissions of non-CO₂ pollutants are not curbed, there is a 66% likelihood of surpassing the 1.5 °C threshold, regardless of reductions to carbon dioxide.

Reducing methane and black carbon emissions is also crucial for limiting the rate of warming in the near-term. It is clear that we must reduce emissions of these pollutants in addition to CO₂, and several broad mitigation measures in areas such as the energy sector tackle the reduction of both.

4. Waiting to cut emissions may have severe, irreversible effects on the planet.

Long-term warming scenarios depend upon carbon dioxide, a gas whose emissions build up in the atmosphere over its long lifetime. Delaying emissions reductions would overshoot the 1.5 °C target, though it is technically possible to return below this threshold through intense mitigation. However, even temporarily overshooting 1.5 °C may have irreversible impacts on our natural systems, including biodiversity loss or pushing past various climate tipping points.

5. Mitigation efforts may not only benefit our climate, but lead to more resilient communities.

Vulnerable communities will be disproportionately affected by changing phenomena, through socioeconomic impacts such as food insecurity, income loss, health impacts, displacement, and increased conflict. Thankfully, the benefits of reducing greenhouse gas emissions are often twofold, as many mitigation strategies also support sustainable development through improvements to water and air quality, public health, and ecosystem stability.

This is especially true when reducing short-lived climate pollutants, such as methane and black carbon, which simultaneously cuts down on air pollution and mitigates health threats such as asthma and other respiratory diseases.

6. More ambition is needed to stay below 1.5 °C.

Even if all countries fulfilled their Nationally Determined Contributions (NDCs) as outlined in the Paris Agreement, there is very high likelihood that we will reach 1.5 °C warming by mid-century and remain above this threshold through year 2100.

Avoiding 1.5 °C global warming requires rapid and intense global reductions in both carbon dioxide and non-CO₂ climate pollutants beyond current NDC pledges.

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Recent technological advances have already shaped our ability to mitigate and adapt to climate change, and new developments will undoubtedly be discovered. In the meantime, the benefits of limiting global warming should inspire us to continue our fight to provide a safe planet for current and future generations.

Remaining below the 1.5 °C global warming target is not a simple feat, but today’s report shows that it is a worthy endeavor. As working group co-chair Valerie Masson-Delmotte stated during the report’s press conference, “Nothing is impossible when you build on collective human intelligence.”