10 New Insights in Climate Science 2018

Full Report

From fires in North America to floods across Asia, many societies have in the last 12 months begun to experience more severe impacts attributable to human-induced climate change. Although predicted by scientists, some of these impacts have come earlier than expected. Published in October, the Intergovernmental Panel on Climate Change’s landmark special report provided an unequivocal warning of the negative impacts of allowing global average temperature increase to go beyond 1.5°C (2.7°F).

Having warmed 1°C since the start of the industrial revolution, humanity is experiencing the warmest average temperature on Earth since the end of the last Ice Age, 12,000 years ago. In 2018, global carbon dioxide emissions from the combustion of fossil fuels are projected to reach a new record high of about 37 billion tons per year. Rising levels of greenhouse gases in the atmosphere are increasing the global average temperature, causing ocean acidification, and perturbing the climate system through, for instance, changed rainfall patterns. Climate change is leading to observed increases in economic losses and human suffering, by displacing vulnerable populations and deepening existing inequalities.



Extreme weather events are now clearly attributable to climate change
  • Increasing frequency and intensity of extreme events can, with higher precision, be linked to climate change
  • 2018 has been a year of record-breaking extremes in the Northern Hemisphere with flooding and locally unprecedented heat waves and wildfires


Growing climate impacts show risks of critical tipping points
  • Changes have been observed in major Earth systems: a weakening of the Atlantic overturning circulation, mass mortality of the world’s coral reefs, and ice loss from the West Antarctic ice sheet has tripled
  • With continued warming, these and other systems can reach points where they rapidly collapse or a major, largely unstoppable transformation  is initiated
  • The world at 2°C warming and beyond is unsafe territory with a risk of crossing a planetary threshold towards a “Hothouse Earth”


Every half degree matters: Large difference in impacts between 1.5°C and 2°C degrees of warming
  • Significantly lower impacts on human health, living conditions, and natural ecosystems, when limiting global warming to 1.5°C instead of 2°C
  • 1.5°C can now be considered a strongly preferable target for the planetary climate boundary


New understanding of the acceleration of sea level rise and its future
  • The rate of ice loss from Antarctica is increasing, now almost twice as high as projected by the latest IPCC assessment (2014)
  • Satellite data confirms that the rate of sea level rise is accelerating
  • Limiting warming to 1.5°C instead of 2°C can avoid the inundation of lands currently home to about 5 million people.


Managing plants and soil: a prerequisite for meeting the Paris Agreement
  • Between 2007 and 2016, land use change was responsible for annual global emissions of, on average, 4.7 billion tons of CO2, which is around 12% of CO2 emissions
  • Natural climate solutions could potentially provide over one-third of the cost-effective climate mitigation needed between now and 2030 to stabilize warming to below 2°C


Options to remove CO2 from the atmosphere are limited
  • Scenarios that have recently been assessed by the IPCC show that the world will need to draw ca 100-1000 billion tons of CO2 out of the air, so-called Carbon Dioxide Removal (CDR), during this century to achieve the 1.5°C target
  • Some CDR options can have co-benefits at small scales but all options run into major scalability and sustainability limitations at large scales
  • This calls for both stronger emissions reductions than was previously assumed, and rapid deployment of CDR techniques


Major socio-technical transformations needed to meet the 1.5°C target
  • Pathways to limit warming to 1.5°C require at least a halving of emissions to 2030
  • Such rapid reductions require transformations of full sociotechnical systems, across all sectors and scales
  • Cities and energy systems are pivotal and there is already considerable momentum in the energy sector that it could see major shifts towards very low emissions, with the right support


Stronger policy measures would reduce climate risks
  • Climate action to limit warming to 1.5°C could save the world in the order of 20 trillion USD and likely benefit a vast majority of the global population
  • Phasing out fossil fuel subsidies would reduce global carbon emissions and strengthen public budgets, but reforms should consider acceptance, effects on poverty, and possible adverse effects such as shifts from gas to coal
  • A comprehensive and dynamic portfolio of policies including standards, regulations, incentives, and carbon pricing would effectively support and accelerate a low-carbon transition


Transformation of food systems needed for global health and reduced greenhouse gas emissions
  • Decarbonizing and building resilience in the world food system is a prerequisite to succeed with the Paris Agreement
  • Dietary shifts away from unhealthy “Western diets” towards reduced meat and dairy consumption are a significant way to reduce greenhouse gas emissions and improve health.
  • 29% of farms worldwide, or 163 million farms, practice forms of sustainable agricultural intensification.


Benefits for global health by addressing climate change
  • Climate change is increasing the numbers of injuries, illnesses, and deaths from, for example, extreme weather and climate events, infectious diseases, poor air quality, and undernutrition
  • Health systems are beginning to track and manage the risks posed by climate change
  • Most mitigation policies have significant health co-benefits, with the magnitude of the co-benefits about the same as the cost of mitigation