Climate 411

Why melting polar ice is a debt we can’t afford to carry

Near Palmer Station, Antarctica. Photo: Alice Alpert

We now know it’s official – 2023 was the warmest year ever recorded.

Citizens across the globe felt the impacts long before it was confirmed. There were unprecedented wildfires in Canada that turned the New York sky orange. Phoenix saw a record-breaking 31 consecutive days with temperatures topping 110 degrees.

Along with these very immediate impacts, we also need to pay attention to the longer-term impacts of climate change. Specifically, when it gets hotter, ice locked in glaciers and ice sheets melts and ends up as water in the ocean. It takes a long time to melt, but eventually all that water raises the level of the ocean.

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The science is clear – climate change is causing more damaging hurricanes in Florida

Flooding in Tampa from Hurricane Idalia. Photo: Andrew Heneen, CC BY 4.0, via Wikimedia Commons

(This post was co-authored by EDF Senior Climate Scientist Ilissa Ocko)

Hurricanes are complicated, and their characteristics depend on a number of factors, which makes it difficult to tease out certain trends and predict the future. But what is scientifically clear is that human-caused climate change is a key reason that hurricanes are more destructive – especially in Florida.

Hurricanes are becoming stronger and faster. They are less predictable and thus more dangerous because there is less time to prepare and evacuate. Flooding from hurricanes is worsening due to higher sea level, more rainfall, and slower storm speeds. 

Florida has always been more vulnerable to hurricanes and tropical storms than any other U.S. state because its exposed, southern location is surrounded by warm waters. There are almost twice as many hurricanes that hit Florida as Texas, the second most impacted state. But shifting atmosphere and ocean conditions from climate change – caused by heat-trapping gases emitted from human activities – are making hurricane season even worse for Floridians. Here’s how:

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Bonn climate talks: The Global Stocktake, oceans, food and nature are issues to watch

EDF’s delegation to the climate talks taking place in Bonn, Germany from June 5 to June 15 give us some insights into the issues they’re following. 

Flags on clear sky. Getty.

Next week, climate negotiators will convene in Bonn, Germany for a two-week negotiation session that will serve as an important marker on the road to the COP28 climate talks in Dubai this November. The outcome of the talks, known as SB58, will set the stage for the negotiations at COP28, giving us an indication of what needs to happen in the months leading up to those pivotal talks.

Every year the climate negotiations become more urgent as we draw closer to the timelines for meeting the Paris Agreement goals. The task is even more challenging when considering the other crises the world faces, like economic disruption, energy insecurity and food scarcity. We need effective solutions that can solve for these multiple challenges simultaneously. The talks in Bonn are an important opportunity to gauge progress and push forward key action points that address these various challenges, in the lead up to COP28, and beyond.

EDF’s delegation to the Bonn climate talks are closely monitoring various important issues inside and around the negotiations. These include the Global Stocktake process, food, fisheries and ocean issues, and efforts to expand high-integrity carbon market cooperation.

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Also posted in Agriculture, Carbon Markets, Forest protection, International, News, Paris Agreement, United Nations / Comments are closed

What you need to know about hurricanes and climate change

Photo: NOAA

This post was co-authored by EDF Postdoctoral Climate Science Fellow Tianyi Sun

Today Hurricane Laura made landfall in Louisiana as a Category 4 hurricane, causing death and destruction. Louisianans and Texans in its path are now mourning and looking ahead to a long and painful recovery.

Laura had winds up to 150 miles per hour, making it one of the strongest hurricanes on record to ever hit the Gulf Coast in the United States. It tied the record for how quickly it intensified, driving questions about the role of climate change in creating and fueling this monster storm.

A look at the latest science

Scientists have been actively studying how climate change affects hurricanes for decades, and the evidence that it can influence several aspects of hurricanes continues to grow.

Overall, climate change is making these already dangerous weather events even more perilous. They are stronger, wetter, slower, and intensify more rapidly. Major storms are occurring more often and piling on heavier rainfall, and scientists anticipate the strongest storms will continue to increase in frequency. Sea level rise, along with stronger winds, are also worsening storm surges, causing more coastal flooding.

All aspects of hurricanes – from formation to track to strength to damages – can be influenced to some degree by climate change, through warmer waters, more moisture in the atmosphere, changing air patterns, and sea level rise.

For some connections, such as how climate change affects hurricane strength and its damages, the science is simple and robust. For other connections, such as how climate change affects hurricane formation and track, the science is more complicated and nuanced.

Here we break down what we know about how climate change affects four key aspects of hurricanes


1. Hurricane formation – competing factors at play
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Four takeaways on climate change and sea level rise in the latest IPCC report

The Intergovernmental Panel on Climate Change has published yet another alarming report about the dangers we face from the climate crisis.

The Special Report on the Ocean and Cryosphere in a Changing Climate synthesizes the latest science on how the oceans and frozen parts of the world have changed, and will continue to change, because of global warming.

More than 100 scientists from 36 countries summarized findings from almost 7,000 peer reviewed research studies. The authors addressed over 30,000 comments from expert reviewers and governments in 80 countries.

A major focus of the report is sea level rise, a climate change impact that is especially serious to those who live in coastal regions – which is more than a quarter of the world’s population. Recent advances in science, such as higher quality data, improved physical understanding, and agreements across modeling studies have improved understanding of the threat of sea level rise.

Here are four of the report’s most important takeaways on sea level rise:

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Also posted in Arctic & Antarctic, Basic Science of Global Warming, Extreme Weather, Greenhouse Gas Emissions, News, Policy, Science / Read 3 Responses

Everything you need to know about climate tipping points

(This post was co-authored by EDF Climate Scientist Ilissa Ocko)

Imagine cutting down a tree. Initially, you chop and chop … but not much seems to change. Then suddenly, one stroke of the hatchet frees the trunk from its base and the once distant leaves come crashing down.

It’s an apt metaphor for one of the most alarming aspects of climate change – the existence of “tipping elements.”

These elements are components of the climate that may pass a critical threshold, or “tipping point,” after which a tiny change can completely alter the state of the system. Moving past tipping points may incite catastrophes ranging from widespread drought to overwhelming sea level rise.

Which elements’ critical thresholds should we worry about passing thanks to human-induced climate change?

You can see the answer on this graphic – and find more information below.

The most immediate and most worrisome threats

  • Disappearance of Arctic Summer Sea Ice – As the Arctic warms, sea ice melts and exposes dark ocean waters that reflect sunlight much less efficiently. This decreased reflectivity causes a reinforcement of Arctic warming, meaning that the transition to a sea-ice free state can occur on the rapid scale of a few decades. Some scientists have suggested that we have already passed this tipping point, predicting that Arctic summers will be ice-free before mid-century.
  • Melting of the Greenland Ice SheetThe Arctic warming feedback described above may one day render Greenland ice-free. Research predicts that the tipping point for complete melt can occur at a global temperature rise of less than two degrees Celsius – a threshold that may be surpassed by the end of this century. While the full transition to an ice-free Greenland will take at least a few hundred years, its impacts include global sea level rise of up to 20 feet.
  • Disintegration of the West Antarctic Ice Sheet – The bottom of this ice sheet lies beneath sea level, allowing warming ocean waters to slowly eat away at the ice. There is evidence that this tipping point has already been surpassed – possibly as early as 2014. Like the Greenland Ice Sheet, full collapse would require multiple centuries, but it could result in sea level rise of up to 16 feet.
  • Collapse of Coral ReefsHealthy corals maintain a symbiotic relationship with the algae that provide their primary food source. As oceans warm and become more acidic, these algae are expelled from the corals in an often fatal process called coral bleaching. Research predicts that most of our remaining coral systems will collapse even before a global temperature rise of two degrees Celsius.

Tipping points in the distant future

  • Disruption of Ocean Circulation Patterns – The Thermohaline Circulation is driven by heavy saltwater sinking in the North Atlantic, but this water is becoming fresher and lighter as glaciers melt in a warming climate. The change in water density may prevent sinking and result in a permanent shutdown of the circulation. Research suggests that weakening of the Thermohaline Circulation is already in progress, but that an abrupt shutdown is unlikely to occur in this century. Some models suggest that these changes may prompt a secondary tipping element in which the subpolar gyre currently located in the Labrador Sea shuts off. Such a change would dramatically increase sea level, especially on the eastern coast of the United States.
  • Release of Marine Methane HydratesLarge reservoirs of methane located on the ocean floor are stable thanks to their current high pressure-low temperature environment. Warming ocean temperatures threaten the stability of these greenhouse gas reservoirs, but the necessary heat transfer would require at least a thousand years to reach sufficient depth, and may be further delayed by developing sea level rise.
  • Ocean AnoxiaIf enough phosphorous is released into the oceans – from sources including fertilizers and warming-induced weathering, or the breakdown of rocks –regions of the ocean could become depleted in oxygen. However, this process could require thousands of years to develop.

Potentially disastrous elements, but with considerable uncertainty

  • Dieback of the Amazon Rainforest Deforestation, lengthening of the dry season, and increased summer temperatures each place stress on rainfall in the Amazon. Should predictions that at least half of the Amazon Rainforest convert to savannah and grasslands materialize, a considerable loss in biodiversity could result. However, the dieback of the Amazon Rainforest ultimately depends on regional land-use management, and on how El Niño will influence future precipitation patterns.
  • Dieback of Boreal Forests – Increased water and heat stress could also lead to a decrease in boreal forest cover by up to half of its current size. Dieback of boreal forests would involve a gradual conversion to open woodlands or grasslands, but complex interactions between tree physiology, permafrost melt, and forest fires renders the likelihood of dieback uncertain.
  • Weakening of the Marine Carbon Pump – One mechanism through which oceanic carbon sequestration takes place is the marine carbon pump, which describes organisms’ consumption of carbon dioxide through biological processes such as photosynthesis or shell building. As ocean temperatures rise, acidification progresses, and oxygen continues to be depleted, these natural systems could be threatened and render the carbon sequestration process less efficient. More research is necessary in order to quantify the timescale and magnitude of these effects.

Tipping elements complicated by competing factors

  • Greening of the Sahara/Sahel As sea surface temperatures rise in the Northern Hemisphere, rainfall is projected to increase over the Sahara and Sahel. This increased rainfall would serve to expand grassland cover in the region, but is balanced by the cooling effect of human-emitted aerosols in the atmosphere.
  • Chaotic Indian Summer MonsoonThe fate of the Indian Summer Monsoon similarly depends upon a balance of greenhouse gas warming and aerosol cooling, which strengthen and weaken the monsoon, respectively. On the timescale of a year, there is potential for the monsoon to adopt dramatic active and weak phases, the latter resulting in extensive drought.

More research necessary to establish as tipping elements

  • Collapse of Deep Antarctic Ocean CirculationAs in the case of the Thermohaline Circulation, freshening of surface waters in the Southern Ocean due to ice melt may slowly alter deep water convection patterns. However, the gradual warming of the deep ocean encourages this convection to continue.
  • Appearance of Arctic Ozone HoleUnique clouds that form only in extremely cold conditions currently hover over Antarctica, serving as a surface for certain chemical reactions and facilitating the existence of the ozone hole. As climate change continues to cool the stratosphere, these “ice clouds” could begin formation in the Arctic and allow the development of an Arctic ozone hole within a year.
  • Aridification of Southwest North America As global temperatures rise, consequential changes in humidity prompt the expansion of subtropical dry zones and reductions in regional runoff. Models predict that Southwest North America will be particularly affected, as moisture shifts away from the southwest and into the upper Great Plains.
  • Slowdown of the Jet Stream A narrow and fast moving air current called a jet stream flows across the mid-latitudes of the northern hemisphere. This current separates cold Arctic air from the warmer air of the south and consequentially influences weather in its formation of high and low pressure systems. A slowing of the jet stream has been observed over recent years. Should slowing intensify, weather patterns could persist over several weeks with the potential to develop into extended extreme weather conditions.
  • Melting of the Himalayan Glaciers – Several warming feedbacks render the Himalayan glaciers vulnerable to dramatic melt within this century, though limitations on data availability complicate further study. Dust accumulation on the mountainous glaciers and the continual melt of snow and ice within the region both prompt a decrease in sunlight reflectivity and amplify regional warming.

Gradual, continuous changes

  • More Permanent El Nino State90 percent of the extra heat trapped on Earth’s surface by greenhouse gases is absorbed by the oceans. Though still under debate, the most likely consequence of this oceanic heat uptake is a gradual transition to more intense and permanent El Nino/Southern Oscillation (ENSO) conditions, with implications including extensive drought throughout Southeast Asia and beyond.
  • Permafrost MeltingAs global temperatures rise and the high latitudes experience amplified warming, melting permafrost gradually releases carbon dioxide and methane into the atmosphere and creates a feedback for even more warming.
  • Tundra Transition to Boreal Forest – Much like the conversion of the Amazon Rainforest and boreal forests to other biomes, tundra environments may transition into forests as temperatures increase. However, this process is more long-term and continuous.

With a range of critical thresholds on the horizon, each tipping element demonstrates the potential implications of allowing climate change to progress unchecked.

As tipping points loom ever closer, the urgency for emissions mitigation escalates in hopes of sustaining the Earth as we know it.

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