This morning I gave an interview on The Weather Channel!   Much of the southwest U.S. is currently in drought, and I was lead author on a recent paper in Science Advances which looks at U.S. drought over the past 1000 years.  We found that while some drought is linked to La Nina, much past variability appears to be the result of atmospheric variability.  This work was done with colleagues at the University of Southern California, University of Washington, and Columbia University.  Check it out!

The interview: www.youtube.com/watch?v=GpNYhX0xKcQ
The paper: advances.sciencemag.org/content/6/32/eaay7268.full

In two new papers, published recently in Scientific Data, we present an extensive compilation of Holocene proxy records and use them to reconstruct global-mean temperature over the past 12,000 years.  The proxy collection represents a vast collection of data and the temperature reconstructions synthesize the data using five methods.  Data and methods have been released alongside the papers, so check it out.

The papers
The proxy database: Kaufman et al., 2020: "A global database of Holocene paleotemperature records"
The temperature reconstructions: Kaufman et al., 2020: "Holocene global mean surface temperature, a multi-method reconstruction approach"

Back in September, I had the wonderful opportunity to do some field work in Colorado.  Colleagues and I traveled to high elevation lakes and fens to take sediment cores.  It was a fun experience, and I've made a write-up of the field work, along with photos, on this page: Ancient Sediment — Lakes and Fens in Colorado.  Take a look!

This morning I did a radio interview!  It was on the KPCW show 'This Green Earth' and concerned a recent Nature Geoscience paper that I worked on with a lot of colleagues, which discusses global-mean temperature changes over the past 2000 years.  You can find the radio interview here (https://www.kpcw.org/post/green-earth-july-30-2019-michael-erb) or on your favorite podcast app by looking for the 'This Green Earth' podcast.

Please give the interview a listen!  I was a little late due to a scheduling mix-up, but I show up around the three minute mark.  Apologies for any details I might have misstated (this is my first radio interview), but all of the main points should be right.  Hopefully I get listeners interested in the fascinating and important nature of this work.  As I say in the interview, proxy data are really cool!

You can read the full text of the paper we're talking about here: Nature Geoscience paper.

Also, the hosts talk a little about a companion paper that colleagues of mine (but not me) worked on, which discusses regional climate variability over this same time period, which you can find here: Nature paper.

Below are some articles about our recent Nature Geoscience paper, 'Consistent multidecadal variability in global temperature reconstructions and simulations over the Common Era' (https://www.nature.com/articles/s41561-019-0400-0), as well as related new papers.

Nature Geoscience - "The great climate conundrum"
Los Angeles Times - "Earth warmed faster in the last few decades than the previous 1,900 years, study says"
CNET - "Recent climate change trends 'unprecedented' in the last 2,000 years"

Our new paper, out today in Nature Geoscience, explores global-mean temperature over the past 2000 years, reconstructed using seven different statistical methods: https://www.nature.com/articles/s41561-019-0400-0.

Results show:
1) The second half of the 20th century warmed more rapidly than any previous time in the last 2000 years, putting the extraordinary rate of current climate change into a long-term context.
2) Before the industrial revolution, volcanic eruptions were the most important forcing of multi-decadal climate variations during this time period.
3) Climate models capture the magnitude of volcanic-forced cooling and natural variability well.

This study was an international collaboration which used a global collection of well-vetted proxy records (such as tree rings, corals, and ice cores) to reconstruct Common Era climate, led by Raphael Neukom at the University of Bern.  Coauthors of this study at Northern Arizona University include Darrell Kaufman, Nicholas McKay, and myself.

An NAU press release about the paper can be read here: https://news.nau.edu/pages-2k/

The two primary methods of investigating past climate are through proxy records (e.g. tree rings, ice cores, and corals) and climate models.  These two methods have different strengths and weaknesses, and paleoclimate data assimilation is a method which aims to utilize the advantages of each to reconstruct past climate.  Our new paper, published today in Climate of the Past (available here: https://www.clim-past.net/15/1251/2019/), explores this method and reconstructs multiple climate fields over the past 2000 years.  Take a look.

Our new paper, published yesterday in Nature (https://www.nature.com/articles/s41586-019-1060-3), has been generating some more news:

Phys.org - "New study shows arctic warming contributes to drought"
Toronto Star - "Research links shrinking sea ice to less rain in south"
EurekAlert! - "Study shows arctic warming contributes to drought"
Ars Technica - "Thousands of years ago, a warm Arctic made mid-latitudes drier"

New paper!  Our paper, published today in Nature, studies the connection between the strength of the Northern Hemisphere latitudinal temperature gradient and mid-latitude net precipitation during the Holocene: https://www.nature.com/articles/s41586-019-1060-3.  The primary finding is that a weaker temperature gradient in the early Holocene is associated with reduced net precipitation in the mid-latitudes, consistent with the idea of weaker mid-latitude cyclones.  Because global climate change is currently weakening this temperature gradient through Arctic amplification, this paper is exceedingly relevant to the study of future changes.  This paper is the result of diligent effort by scientists here at Northern Arizona University (Cody Routson, Nick McKay, Darrell Kaufman, and myself) as well as co-authors at other universities (Hugues Goosse, Bryan Shuman, Jessica Rodysill, and Toby Ault).

Early press for the paper:
NAU News - "As the Arctic warms, temperate regions dry out, with likely effects on society"
CTV News - "Strong connection: Research links shrinking sea ice to less rain in south"