Significant global variability in climate can be traced back into the Paleozoic era when an explosion of multicellular life took place within the oceans. There is recent evidence of a possible early snowball earth episode that occurred as a result of the Great Oxygenation event as early as 2.4-2.1 million years ago in the Paleoproterozoic era. A snowball earth is a hypothetical scenario that some scientists suggest could have occurred at least once in Earth’s record, where the entire or nearly entire Earth was covered in ice. An explosion of anaerobic organisms producing oxygen as a by-product is thought to have lowered methane levels in the atmosphere. Because solar activity was lower than modern times (Early Sun Paradox), it was thought that lowering of methane, a greenhouse gas, would ultimately reduce global temperatures leading to the snowball earth. Many pro-snowball earth scientists believe that these types of events likely occur due to a positive feedback effect. Once, global temperatures sufficiently cooled, a runaway effect would occur that would keep global temperatures in a decline. However, there is still a great amount of disagreement between scientists in regards to the Huronian glaciation which could be the longest lasting glacial period in earth’s history.
Scientists have found some evidence to support the case of the Huronian glaciations to have covered the entire Earth as such. Such evidence is that the global distribution of Sturtian and Marinoan glacial deposits, suggest at this geologic time, that most land mass were indeed covered in a glacier. The warmer parts of the surface ocean during this time contain glacial marine deposits and thick limestone type rock which suggest a much colder regime. Further, paleomagnetic data suggests that glacial sediment has been found near the paleo-equator, or the location of the equator during this geologic time.
However, some evidence would seem to suggest that snowball earth was non-existent. Such evidence comes from rocks in Oman, that have produced evidence of many cycles of hot and cold regimes in the Paleoproterozoic era’s. Other evidence against this hypothesis is that the global deposits of glacial marine sediment are not the same age everywhere which would seem to suggest that the collective nature of all the global glacial sediment was not deposited in a single time that a snowball earth would produce. Finally, indications of an open ocean during this time do exist. Indications of open water such as biomarkers of phototrophism, numerous examples of wave ripples and ice rafted debris have been found to travel extensive distances across the paleo-oceans. While arguments still exist in whether the Earth was completely covered in ice, it is always interesting to think about how different Earth’s climate could have been.
For more interesting articles on the past and future states of the climate, be sure to click here!
© 2018 Meteorologist Allan Diegan
Everyone talks about what the “high for today” will be when looking at weather forecasts for the next few days. While this is important, seldom do people consider what the “low for tonight” may be, but the lows are just as essential as the highs. Nightly minimum temperatures, just like daily maximum temperatures, have both significant ecological and agricultural impacts, as well as effects on public health.
First, consider the ecological impacts. An increase in the lowest minimum temperature in winter may permit the eggs of insects, such as the Southern Pine Beetle, to survive winters in regions where colder temperatures in the past prohibited survival (Ayres et al. 2011). This invasive species has already invaded the New Jersey Pinelands, and threatens to do considerably more damage. It is hypothesized that the reason for the invasion is at least in part a function of warmer extreme minimums. This rise in lowest minimum may also help facilitate cold-tolerance for non-invasive species, such as the bark beetle found in the western conifer forests of United States and Canada, meaning these bark beetles would be able to live throughout the winter season with an increase in cold tolerance (Bentz et al. 2010). This winter survival of species is enough to change an ecosystem.
Minimum temperatures affect agriculture as well. Hatfield et al. (2011) reports that plant respiration rates actually slow down as minimum temperatures increase above an optimum level; meaning that overall crop yield will be reduced. In another study, Hatfield and Prueger (2015) have shown that the effects of increased minimum temperatures have decreased the ability of maize to efficiently produce grain. The decreased crop yield due to these temperatures could have devastating effects on world hunger.
Finally, human and public health is also an important function of minimum temperatures, one example being the rise of heat waves in the hot summer months. A summer increase in the minimum temperatures may be indicative of greater heat stresses being placed on individuals or families without air conditioning at night, especially during heat waves. This detrimentally impacts the ability of sensitive populations to recover from previous daytime heat, as they are not able to cool down at night. Pollen season could also be affected as well. A study published by Zhang et al. (2015) shows that allergenic pollen season timing and levels in the US are partially associated with the number of Frost Free Days (FFD), where FFD is defined as the interval between the last frost day each spring and first frost day each fall. The rise of minimum temperatures in the fall and winter could possibly increase the FFD, which might affect pollen season length.
For more information, and some real analyzed data on the topic of minimum temperature extremes, the Office of the New Jersey State Climatologist has a short study on their website, specifically using COOP stations in New Jersey. Find it here!
As always, for more great articles on our changing climate, be sure to visit here!
Ayres, Matthew P., Sharon J. Martinson and Nicholas A. Friedenberg, 2011: Southern pine beetle ecology: populations within stands, Southern Pine Beetle II. General Technical Report., 140, 75-89.
Bentz, Barbara J., Jacques Regniere, Christopher J. Fettig, E. Matthew Hansen, Jane L. Hayes, Jefferey A. Hicke, Rick G. Kelsey, Jose F. Negron, and Steven J. Seybold, 2010: Climate Change and Bark Beetles of the Western United States and Canada: Direct and Indirect Effects, BioScience, 60, 603-613.
Hatfield, Jerry L., Kenneth J. Boote, Bruce A. Kimball, Lewis H. Ziskz, Roberto C. Izaurralde, 2011: Climate Impacts on Agriculture: Implications for Crop Production, Publications from USDA-ARS / UNL Faculty. 1350.
Hatfield, Jerry L., John H. Prueger, 2015: Temperture extremes: Effect on plant growth and development, Weather and Climate Extremes, 10, 4-10.
Zhang, Yong, Leonard Bielroy, Zhongyuan Mi, Ting Cai, Alan Robock, and Panos Georgopoulous, 2015: Allergenic pollen season variations in the past two decades under changing climate in the United States, Global Change Biology, 21, 1581-1589.
©2018 Meteorologist Joey Fogarty
Climate Change, Again in Contention As Rail Enters Honolulu Corridor (Credit: HART & Meteorologist Jessica Olsen)
DISCUSSION: Nearly 4 months after our initial reporting on possible impacts to HART (Honolulu Authority for Rapid Transportation) due to climate change, concerns are still rising as projections for climate change impacts are expected to bring more than a 3-foot change to the latter part of the corridor by the year 2100.
The Hawai’i Climate Change Mitigation & Adaptation Commission is expected to “provide direction, facilitation, coordination and planning among state and county agencies and other partners about climate change mitigation and climate change resiliency strategies, including but not limited to, sea level rise adaptation, water and agricultural security and natural resource conservation.”
Interest involving climate change consequences are focused on coastal flooding, and sea level rise which could result in 8 ground level rail stations in the Honolulu area. HART indicates its adaptation efforts by already providing an elevated guideway, thus reducing any future sea-level rise ramifications. However, research conducted by the Hawai’i Climate Change Mitigation & Adaptation Commission estimates that the support columns aiding the guideways could be underwater in some instances, making some stations’ entryways inaccessible.
Thursday, July 19th State Rep. Sylvia Luke, chairwoman of the House Finance Committee indicated to HART that adjustments should be made to the rail line brining it along King Street to the University of Hawaii rather than by way of Ala Moana Boulevard due to mounting concern of sea-level rise along Ala Moana Boulevard. Some are predicting that this 3-feet of rise could happen in as little as 20 years, putting Kakaako in danger of flooding critical access points along the rail line.
Some drawback has come from Mayor Kirk Caldwell indicating HART can respond to these climate issues without altering the route. He notes the route was set to serve a substantial population in its current plans. Both parties are discussing issues brought by this climate debate such as the public-private partnerships contracts that could ultimately bring additional public scrutiny over funding.
For more in climate change impacts visit the Global Weather and Climate Center!
Our initial article on climate change impacts to HART!
© 2018 Meteorologist Jessica Olsen
“HART.” Honolulu Rail Transit, honolulutransit.org/.
“Hawaiʻi Climate Change Mitigation & Adaptation Commission.” Hawaiʻi Climate Adaptation Portal, 14 Sept. 2017, climateadaptation.hawaii.gov/commission/.
Likelihood of El Nino Increases for Fall and Winter 2018-19 (Credit: Climate Prediction Center, NWS)
Within the past week, the Climate Prediction Center raised the likelihood for El Nino to occur this fall and winter. Fall and Winter 2018 now possess, respectively, a 65 and 70 percent likelihood for occurring. The reasoning for this increase in percentage is due to the above-average temperatures in the tropical Pacific. June 2018 came in 0.11 degrees Celsius above the long-term temperature average. Based upon multiple climate models run by the Climate Prediction Center, it is predicted that come fall, temperatures will reach the El Nino threshold of 0.5 degrees Celsius above average.
A recent Kelvin wave which sloshes around water and creates up and down welling occurred in this region. Kelvin waves are not like waves that can be observed at any beach. These are planetary waves due to their immense scale. These waves do not curl and crash, rather, they slowly roll up into broad peaks and down into valleys that change the depth of the ocean water. Kelvin waves that interfere with El Nino only move eastward along the equator. In this instance, a down welling Kelvin wave made its way eastward across the pacific. In a down welling phase, winds shift from west to east bringing a warm layer of water which is usually in the western Pacific eastward. The warm layer of water pushes down the thermocline—boundary between warmer water near the surface and colder, deeper water. The downward push makes it harder for the colder water to affect the surface. This causes above-average temperatures and helps fuel El Nino development.
To understand the prediction aspect of El Nino, we must first understand what exactly El Nino is and how it affects the United States and the globe. El Nino refers to the warming of surface ocean water in the central and eastern Pacific. Low-level surface winds gradually weaken and, in some cases, switch direction from east to west (easterly winds), to west to east (westerly winds). This helps decrease upwelling which brings cooler water to the surface. El Nino irregularly occurs every three to five years and lasts usually nine to twelve months. This climate phenomenon alters weather patterns all over the globe during the winter months in the Northern Hemisphere. Warmer-than-average temperatures occur over western and central Canada along with the western and northern United States during El Nino. For the Gulf Coast, wetter than average conditions are more likely to occur. On the other side of the spectrum, drier than average conditions are more likely to take place in the Ohio Valley and Pacific Northwest.
Being able to predict El Nino conditions for the coming winter months is of utmost importance for a wide variety of regions around the Earth. El Nino can shift and even deplete weather patterns, so it is vital to understand the severity and likelihood of conditions for each El Nino.
To learn more about other interesting stories related to global climate issues, be sure to click on the following link: www.globalweatherclimatecenter.com/climate
©2018 Weather Forecaster Alec Kownacki
One of the biggest threats from climate change is sea level rise. Heightened sea levels threaten coastal communities, which are home to 39% of the population. A number of factors contribute to sea level rise, but one of the biggest contributors is melting land ice from countries like Greenland. Melting land ice is problematic because, unlike sea ice, it is not already part of the ocean system. Think of it like a full glass of water – if ice is already in the glass, its melting does not cause the glass to overflow. The volume of the ice is already accounted for, and as it melts, the volume does not change. However, if you add ice to the full glass, there is more water volume, and the glass will overflow.
Once land ice starts to melt, it becomes more likely that this ice will continue to melt. This is because of something called the ice-albedo feedback.
Let’s define some of these terms before we get into the nitty-gritty.
Albedo is a measure of how reflective a surface is, on a scale from 0 (absorbs all sunlight) to 1 (reflects all sunlight). Darker surfaces have lower albedo values, while lighter surfaces have higher albedo. For example, old asphalt has an albedo of about 0.1, while fresh snow has an albedo of about 0.75.
A feedback, also known as a feedback loop, is a process where one step affects the rest of the process. Feedback loops can be positive, meaning that the process intensifies; or negative, meaning that the process diminishes. Ice-albedo feedback is a positive feedback.
As land ice melts, the color of the surface becomes darker. Ice is whiter than the pools of water that form in it, as shown in the image above. Because darker surfaces have lower albedo, or absorb more solar radiation, they are hotter than lighter surfaces. Think of walking barefoot in summer – stepping on a blacktop is much more painful than a light-colored sidewalk. As the darker surface get hotter, it becomes much easier for the surrounding ice to melt. This is why ice-albedo is a positive feedback. Ice melts, the surface gets warmer, more ice melts, causing the surface to warm, so on and so forth.
Melting land ice and the effect of the ice-albedo feedback may seem like too big of a problem to solve. However, individual efforts can have an impact! One way to conserve energy is to always un-plug your phone and/or laptop chargers before you leave the house for the day. Did you know your chargers use energy when they’re plugged in, regardless of whether there’s a gadget on the other end? Unplugging them goes a long way in not only saving energy that is commonly generated by harmful fossil fuels, but it will also save you money on your energy bill.
To learn more about Earth’s climate and how it is changing, visit https://www.globalweatherclimatecenter.com/climate
©2018 Meteorologist Margaret Orr
Photo from NASA Earth Observatory
DISCUSSION: There are currently dozens of wildfires burning across the western U.S. The picture above is actually a satellite image of smoke from fires (indicated by red squares) in December 2017 in southern California (photo credit: NBC 4 Los Angeles and NASA). It seems like wildfires and fire seasons have gotten worse (more fires and/or greater acreage burned) in recent years. Part of the reason for this is human-caused climate change. Studies have indicated that an increasing average global temperature due to an increase in greenhouse gases can cause warmer, drier, and windier conditions to intensify and occur more frequency in some regions (e.g., western North America), all conditions that are especially dangerous should a fire be ignited. In addition, studies have indicated that human-caused climate change can cause wetter winter and springs in some locations, fostering more plant growth. When this increased growth dries out over the summer dry season, it can provide additional fuel for fires.
But, climate change doesn't tell the whole story. To get a fire, there must be an ignition source. Lightning and human ignition (e.g., fireworks, camp fires left unattended, cigarette butts, etc.) are the primary ignition sources. More people moving into wilderness areas provides more opportunity for accidents to happen. It is difficult to determine whether global climate change has had any influence on thunderstorm occurrence. Regardless, thunderstorms are going to occur with or without people and their influence on the climate.
Fires are a natural part of many ecosystems. They help thin forests, allowing for more diversity to occur in a forest and for the remaining trees to have more space and nutrients to grow (i.e., healthier trees). In addition, repeated smaller fires can burn up fuel (e.g., twigs, leaves, etc.) before they can accumulate on the forest floor, preventing a future larger fire. With more people living in wilderness areas and the resulting need for more aggressive fire fighting, fuel potentially builds up, increasing the risk of more dangerous fires in the future.
The main takeaway message here is that people indirectly influence fire risk via our influence on climate. They also more directly influence fire risk by moving into wilderness areas and potentially increasing the risk of igniting a fire. Obviously, it is a tragedy when people lose their homes and/or lives in a fire. But, it is important to keep in mind that fires left to burn away from people are not necessarily a bad thing.
Finally, given that it is Independence Day in the U.S., please be cognizant of the fire risk should you decide to shoot off fireworks. If you live in a region that has been especially warm and dry lately, it may be best to leave the fireworks to the professionals.
To learn more about other global climate stories and/or topics, be sure to click here! For more information on fire weather, click here!
©2018 Meteorologist Dr. Ken Leppert II